Virtual network configuration and management system for satellite communication system

ABSTRACT

In a mobile satellite system, a system for providing satellite communication between multiple users in a virtual network arrangement includes first and second mobile earth terminals (METs) responsively connected to and registering with the mobile satellite system. The first MET selects a virtual network identifier (VN ID) representing a virtual network group including the first and second METs to establish voice communication therewith and transmits the VN ID to a central controller. The central controller receives the VN ID from the first MET, validates the first MET for communication, validates the VN ID, allocates a frequency for the virtual network group, and broadcasts the message to the virtual network group including the second MET informing the virtual network group of the allocated frequency and the voice communication associated therewith. The second MET tunes to the frequency in response to the message broadcast by the central controller.

RELATED APPLICATIONS

This application is a continuation-in-part application fromInternational application number PCT/US96/19120 filed Nov. 29, 1996,entitled "VIRTUAL NETWORK CONFIGURATION AND MANAGEMENT SYSTEM FORSATELLITE COMMUNICATIONS SYSTEM."

This application also claims priority from: U.S. provisional applicationSer. No. 60/007,742 filed on Nov. 30, 1995 entitled "COMMUNICATIONSGROUND SEGMENT SYSTEMS ARCHITECTURE"; U.S. provisional application Ser.No. 60/007,749 filed on Nov. 30, 1995 entitled "GROUP CONTROLLER"; allof which are hereby incorporated by reference.

This application incorporates by reference the following U.S. patentapplications: U.S. application Ser. No. 08/565,036, filed Nov. 30, 1995,entitled "FRAUD DETECTION AND USER VALIDATION SYSTEM FOR MOBILE EARTHTERMINAL COMMUNICATION DEVICE"; U.S. patent application Ser. No.08/700,943 filed on Aug. 21, 1996 entitled "NETWORK OPERATIONSCONTROLLER FOR MOBILE EARTH TERMINAL SATELLITE COMMUNICATIONS SYSTEM";U.S. patent application Ser. No. 08/728,227 filed on Oct. 10, 1996entitled "IMPROVED NETWORK CONTROL CENTER FOR SATELLITE COMMUNICATIONSYSTEM"; U.S. patent application Ser. No. 08/654,198 filed on May 28,1996 entitled "COMMUNICATION PROTOCOL FOR MOBILE EARTH TERMINALCOMMUNICATION DEVICE USED IN MOBILE SATELLITE COMMUNICATION SYSTEM.

TECHNICAL FIELD

The present invention relates generally to a satellite trunked radioservice system for satellite communication, and more particularly, to avirtual network configuration and management system for satellitecommunication utilizing a shared satellite demand period circuitassociated with private voice networks.

BACKGROUND ART

An overview of the satellite network system is illustrated in FIG. 1.The satellite network system design provides the capability for METs andFESs to access one or more multiple beam satellites located ingeostationary orbit to obtain communications services.

The heart of the satellite network system for each of the networks isthe Network Control System (NCS) which monitors and controls each of thenetworks. The principal function of the NCS is to manage the overallsatellite network system, to manage access to the satellite networksystem, to assign satellite circuits to meet the requirements of mobilecustomers and to provide network management and network administrativeand call accounting functions.

The satellites each transmit and receive signals to and from METs atL-band frequencies and to and from Network Communications Controllers(NCCs) and Feederlink Earth Stations (FESs) at Ku-band frequencies.Communications at L-band frequencies is via a number of satellite beamswhich together cover the service area. The satellite beams aresufficiently strong to permit voice and data communications usinginexpensive mobile terminals and will provide for frequency reuse of theL-band spectrum through inter-beam isolation. A single beam generallycovers the service area.

The satellite network system provides the capability for mobile earthterminals to access one or more multiple beam satellites located ingeostationary orbit for the purposes of providing mobile communicationsservices. The satellite network system is desired to provide thefollowing general categories of service:

Mobile Telephone Service (MTS). This service provides point-to-pointcircuit switched voice connections between mobile and public switchedtelephone network (PSTN) subscriber stations. It is possible for callsto be originated by either the mobile terminal or terrestrial user.Mobile terminal-to-mobile terminal calls are also supported.

Mobile Radio Service (MRS). This service provides point-to-point circuitswitched connections between mobile terminal subscriber stations andsubscriber stations in a private network (PN) which is not a part of thePSTN. It is possible for calls to be originated from either end. Mobileterminal-to-mobile terminal calls are also supported.

Mobile Telephone Cellular Roaming Service (MTCRS). This service providesMobile Telephone Service to mobile subscribers who are also equippedwith cellular radio telephones. When the mobile terminal is within rangeof the cellular system, calls are serviced by the cellular system. Whenthe mobile terminal is not in range of the cellular system, the MTCRS isselected to handle the call and appears to the user to be a part of thecellular system. When the mobile terminal is not in range of thecellular system, the MTCRS is selected to handle the call and appears tothe user to be a part of the cellular system. It is possible for callsto be originated either from the MET or the PSTN. Mobileterminal-to-mobile terminal calls are also supported.

Mobile Data Service (MDS). This service provides a packet switchedconnection between a data terminal equipment (DTE) device at a mobileterminal and a data communications equipment (DCE)/DTE device connectedto a public switched packet network. Integrated voice/data operation isalso supported.

The satellites are designed to transmit signals at L-band frequencies inthe frequency band 1530-1559 MHz. They will receive L-band frequenciesin the frequency band 1631.5-1660.5 MHz. Polarization is right handcircular in both bands. The satellites will also transmit in the Kufrequency band, 10,750 MHz to 10,950 MHz, and receive Ku-band signals inthe frequency band 13,000 to 13,250 MHz.

The satellite transponders are designed to translate communicationssignals accessing the satellite at Ku-band frequencies to an L-bandfrequency in a given beam and vice versa. The translation will be suchthat there is a one-to-one relation between frequency spectrum atKu-band and frequency spectrum in any beam at L-band. The satellitetransponders will be capable of supporting L-band communications in anyportion of the 29 MHz allocation in any beam.

Transponder capacity is also provided for Ku-band uplink to Ku-banddown-link for signalling and network management purposes between FESsand NCCs. The aggregate effective isotropic radiated power (AEIRP) isdefined as that satellite e.i.r.p. that would result if the totalavailable communications power of the communications subsystem wasapplied to the beam that covers that part of the service area. Some ofthe key performance parameters of the satellite are listed in FIG. 2.

The satellite network system interfaces to a number of entities whichare required to access it for various purposes. FIG. 3 is a contextdiagram of the satellite network system illustrating these entities andtheir respective interfaces. Three major classes of entities are definedas user of communications services, external organizations requiringcoordination, and network management system.

The users of satellite network communications services are MET users whoaccess the satellite network system either via terrestrial networks(PSTN, PSDN, or Private Networks) or via METs for the purpose of usingthe services provided by the system. FES Owner/Operators are thoseorganizations which own and control FESs that provide a terrestrialinterface to the satellite network. When an FES becomes a part of thesatellite network, it must meet specified technical performance criteriaand interact with and accept real-time control from the NCCs. FESOwner/Operators determine the customized services that are offered andare ultimately responsible for the operation and maintenance of the FES.Customers and service providers interact with the Customer ManagementInformation System within the Network Management System.

The satellite network system interfaces to, and performs transactionswith, the external organizations described below:

Satellite Operations Center (SOC): The SOC is not included in thesatellite network ground segment design. However, the satellite networksystem interfaces with the SOC in order to maintain cognizance of theavailability of satellite resources (e.g. in the event of satellitehealth problems, eclipse operations, etc.) and, from time to time, toarrange for any necessary satellite reconfiguration to meet changes intraffic requirements.

NOC: The satellite network system interfaces with the satellites locatedtherein via the NOC for a variety of operational reasons includingmessage delivery and coordination.

Independent NOCs: The satellite network system interfaces with outsideorganizations which lease resources on satellite network satellites andwhich are responsible for managing and allocating these resources in amanner suited to their own needs.

Other System NOCs: This external entity represents outside organizationswhich do not lease resources on satellite network satellites but withwhom operational coordination is required.

The satellite network management system (NMS) is normally located at anadministration's headquarters and may comprise three major functionalentities; Customer Management Information System (CMIS), NetworkEngineering, and System Engineering (NE/SE). These entities performfunctions necessary for the management and maintenance of the satellitenetwork system which are closely tied to the way the administrationintends to do business. The basic functions which are performed by CMIS,Network Engineering, and System Engineering are as follows:

Customer Management Information System: This entity provides customersand service providers with assistance and information including problemresolution, service changes, and billing/usage data. Customers includeindividual MET owners and fleet managers of larger corporate customers.Service providers are the retailers and maintenance organizations whichinteract face to face with individual and corporate customers.

Network Engineering: This entity develops plans and performs analysis insupport of the system. Network Engineering analyzes the requirements ofthe network. It reconciles expected traffic loads with the capabilityand availability of space and ground resources to produce frequencyplans for the different beams within the system. In addition, NetworkEngineering defines contingency plans for failure situations.

System Engineering: This entity engineers the subsystems, equipment andsoftware which is needed to expand capacity to meet increases in trafficdemands and to provide new features and services which become marketableto subscribers.

The satellite network system comprises a number of system elements andtheir interconnecting communications links as illustrated in FIG. 4. Thesystem elements are the NOC, the NCC, the FES, the MET, the RemoteMonitor Station (RMS), and the System Test Station (STS). Theinterconnecting communications links are the satellite networkInternetwork, terrestrial links, the MET signaling channels, theInterstation signaling channels, and the MET-FES communicationschannels. The major functions of each of the system elements are asfollows:

NOC. The NOC manages and controls the resources of the satellite networksystem and carries out the administrative functions associated with themanagement of the total satellite network system. The NOC communicateswith the various internal and external entities via a local area network(LAN)/wide area network (WAN) based satellite network Internetwork anddial-up lines.

NCC. The NCC manages the real time allocation of circuits between METsand FESs for the purposes of supporting communications. The availablecircuits are held in circuit pools managed by Group Controllers (GCs)within the NCC. The NCC communicates with the NOC via the satellitenetwork Internetwork, with FESs via Ku-to-Ku band interstation signalingchannels or terrestrial links, and with mobile terminals via Ku-to-Lband signaling channels.

FES. The FES supports communications links between METs, the PSTN,private networks, and other MTs. Once a channel is established with anMET, call completion and service feature management is accomplished viaIn-Band signaling over the communication channel. Two types of FESs havebeen defined for the satellite network system; Gateway FESs and BaseFESs. Gateway FESs provide MTS, MRS, MTCRS and NR services. Base FESsare for like services and/or value added services.

MET. The MET provides the mobile user access to the communicationschannels and services provided by the satellite network system. A rangeof terminal types has been defined for the satellite network system.

RMS. The RMS monitors L-band RF spectrum and transmission performance inspecific L-band beams. An RMS is nominally located in each L-band beam.Each RMS interfaces with the NOC via either a satellite or terrestriallink.

STS. The STS provides an L-band network access capability to support FEScommissioning tests and network service diagnostic tests. The STS iscollocated with, and interfaced to, the NOC.

Communications channels transport voice, data and facsimiletransmissions between METs and FESs via the satellite. Connectivity forMET-to-MET calls is accomplished by double hopping the communicationschannels via equipped FESs. Signaling channels are used to set up andtear down communications circuits, to monitor and control FES and METoperation, and to transport other necessary information between networkelements for the operation of satellite network. The system providesOut-of-Band and Interstation signaling channels for establishing callsand transferring information. In-Band signaling is provided onestablished communications channels for supervisory and featureactivation purposes. A detailed description of the satellite networksignaling system architecture is provided in L. White, et al., "NorthAmerican Mobile Satellite System Signaling Architecture," AIAA 14thInternational Communications Satellite Conference, Washington, D.C.(March 1992), incorporated herein by reference.

The satellite network Internetwork provides interconnection among themajor satellite network ground system elements such as the NOCs, NCCs,and Data Hubs, as well as external entities. Various leased and dial-uplines are used for specific applications within the satellite networksystem such as backup interstation links between the NCC and FESs andinterconnection of RMSs with the NOC.

The primary function of the NOC is to manage and control the resourcesof the satellite network system. FIG. 5 is a basic block diagram of theNOC and its interface. The NOC computer is shown with networkconnections, peripheral disks, fault tolerant features, and expansioncapabilities to accommodate future growth. The NOC software isrepresented as two major layers, a functional layer and a support layer.The functional layer represents the application specific portion of theNOC software. The support layer represents software subsystems whichprovide a general class of services and are used by the subsystems inthe functional layer.

The application specific functions performed by the NOC are organizedaccording to five categories: fault management, accounting management,configuration management, performance management, and securitymanagement. The general NCC Terminal Equipment (NCCTE) configurationshowing constituent equipment includes: processing equipment,communications equipment, mass storage equipment, man-machine interfaceequipment, and optional secure MET Access Security Key (ASK) storageequipment. The Processing Equipment consists of one or more digitalprocessors that provide overall NCC control, NCS call processing,network access processing and internetwork communications processing.

The Communications Equipment consists of satellite signaling andcommunications channel units and FES terrestrial communication linkinterface units. The Mass Storage Equipment provides NCC networkconfiguration database storage, call record spool buffering anexecutable program storage. The Man-Machine Interface Equipment providesoperator command, display and hard copy facilities, and operator accessto the computer operating systems. The MET ASK storage Equipmentprovides a physically secure facility for protecting and distributingMET Access Security Keys.

The NCCTE comprises three functional subsystems: NCCTE Common EquipmentSubsystem, Group Controller Subsystem, and Network Access Subsystem. TheNCCTE Common Equipment subsystem comprises an NCC Controller, NCCTE massstorage facilities, and the NCCTE man-machine interface. The NCCController consists of processing and database resources which performfunctions which are common to multiple Group Controllers. Thesefunctions include satellite network Internetwork communications, centralcontrol and monitoring of the NCCTE and NCCRE, storage of the networkconfiguration, buffering of FES and Group Controller call accountingdata, transfer of transaction information to the Off-line NCC andcontrol and monitoring of FESs.

The Mass Storage element provides NCC network configuration databasestorage, call accounting data spool buffering, and NCCTE executableprogram storage. The Man-machine Interface provides Operator command anddisplay facilities for control and monitoring of NCC operation andincludes hard copy facilities for logging events and alarms. A GroupController (GC) is the physical NCC entity consisting of hardware andsoftware processing resources that provides real time control accordingto the CG database received from the NOC.

The Group Controller Subsystem may incorporate one to four GroupControllers. Each Group Controller maintains state machines for everycall in progress within the Control Group. It allocates and de-allocatescircuits for FES-MET calls within each beam of the system, managesvirtual network call processing, MET authentication, and providescertain elements of call accounting. When required, it providessatellite bandwidth resources to the NOC for AMS(R)S resourceprovisioning. The Group Controller monitors the performance of callprocessing and satellite circuit pool utilization. It also performs METmanagement, commissioning and periodic performance verification testing.

The Network Access Subsystem consists of satellite interface channelequipment for Out-of-Band signaling and Interstation Signaling which areused to respond to MET and FES requests for communications services. TheNetwork Access Processor also includes MET communications interfacesthat are used to perform MET commission testing. In addition, thesubsystem includes terrestrial data link equipment for selected FESInterstation Signaling.

The principal function of the FES is to provide the required circuitswitched connections between the satellite radio channels, which providecommunications links to the mobile earth terminals, and either the PSTNor PN. FESs will be configured as Gateway Stations (GS) to provide MTSand MTCRS services or Base Stations to provide MRS services (describedin detail below). Gateway and Base functions can be combined in a singlestation.

The FES operates under the real time control of the NetworkCommunications Controller (NCC) to implement the call set-up andtake-down procedures of the communications channels to and from theMETs. Control of the FES by the NCC is provided via the interstationsignaling channels. An FES will support multiple Control Groups andVirtual Networks. The FES is partitioned into two major functionalblocks, the FES RF Equipment (FES-RE) and the FES Terminal Equipment(FES-TE). The principal function of the FES-RE is to provide the radiotransmission functions for the FES. In the transmit direction itcombines all signals from the communications and interstation signalingchannel unit outputs from the FES-TE, and amplifies them and up-convertthese to Ku-Band for transmission to the satellite via the antenna. Inthe receive direction, signals received from the satellite aredown-converted from Ku-Band, amplified and distributed to the channelunits within the FES-TE. Additional functions include satellite inducedDoppler correction, satellite tracking and uplink power control tocombat rain fades.

The principal function of the FES-TE is to perform the basic callprocessing functions for the FES and to connect the METs to theappropriate PSTN or PN port. Under control of the NCC, the FES assignscommunications channel units to handle calls initiated by MET or PSTNsubscribers. The FES-TE also performs alarm reporting, call detailrecord recording, and provision of operator interfaces.

For operational convenience, an FES may in some cases be collocated withthe NCC. In this event, the NCC RF Equipment will be shared by the twosystem elements and the interstation signaling may be via a LAN.Connection to and from the PSTN is via standard North Americaninterconnect types as negotiated with the organization providing PSTNinterconnection. This will typically be a primary rate digitalinterconnect. Connection to and from private networks is via standardNorth American interconnect types as negotiated with the organizationrequesting satellite network service. This will typically be a primaryrate digital interconnect for larger FESs or an analog interconnect forFESs equipped with only a limited number of channels may be employed.

It has been discovered that there is a general need for an integratedmobile telephone that can be used to transmit to, and receive from, tocommunicate in a virtual network arrangement that allows each member ofthe group to hear what any other user is saying. Each member of thegroup can also talk when needed. The system behaves like a radiomulti-party line where several parties communicate over the samecommunication channel. Public services and law enforcement agencies aretypical users of this service, which is normally provided by eithertraditional terrestrial radio networks or by the more recent trunkedradio systems. These trunked systems, generally in the 800-900 MHz band,provide groups of end users with virtual network systems by assigningfrequencies on a demand basis. In this connection, however, it has beendiscovered that an integrated mobile communication device is needed thatprovides this ability to communicate in a virtual network of a satellitecommunications system.

It has also been discovered the need for a nationwide and regionalpoint-to-multipoint mobile communication service that is not limited incoverage.

SUMMARY OF THE INVENTION

It is a feature and advantage of the present invention to provide anintegrated mobile telephone that can be used to transmit and receive ina virtual network arrangement that allows each member of the group tohear what any other user is saying.

It is another feature and advantage of the present invention to permiteach member of the group to talk when needed, and to provide a systemthat behaves like a radio multi-party line.

It is a further feature and advantage of the present invention toprovide an integrated mobile communication device that can communicatein a virtual network of a satellite network.

It is another feature and advantage of the present invention to providean inexpensive virtual network satellite service to the owner of thegroup.

It is another feature and advantage of the present invention to minimizethe call set-up time for one shared circuit per virtual network.

It is another feature and advantage of the present invention togenerally effectively and efficiently effectuate transmissions betweenmobile communication devices and the satellite network in a virtualnetwork environment by utilizing an efficient communication protocol.

It is another feature and advantage of the invention to provide anationwide and regional point-to-multipoint mobile communication servicethat is not limited in coverage.

The present invention is based, in part, on the desirability ofproviding point-to-multipoint circuit switched connections betweenmobile terminal subscriber stations and a central base station in avirtual network. Mobile users are able to listen to two-wayconversations and to transmit.

To achieve these and other features and advantages of the presentinvention, a mobile communication system is provided in a mobilesatellite system. The mobile satellite system includes a satellitecommunication switching office having a satellite antenna forreceiving/transmitting a satellite message via a satellite from/to avehicle using a mobile communication system, a satellite interfacesystem, a central controller receiving/transmitting the satellitemessage from/to the satellite communication switching office issued fromthe vehicle via the satellite and the satellite interface system. Themobile communication system includes a user interface system providing auser interface through which a user has access to services supported bythe mobile satellite system, and an antenna system providing aninterface between the mobile communication system and the mobilesatellite system via the satellite interface system, and receiving afirst satellite message from the satellite and transmitting a secondsatellite message to the satellite. The antenna system includes anantenna including one of a directional and an omnidirectionalconfiguration, a diplexer, an amplifier, a low noise amplifier, a beamsteering unit when the antenna is of the directional configuration, andat least one of a compass and sensor to determine vehicle orientation.The mobile communication system also includes a transceiver system,operatively connected to the antenna system, including a receiver and atransmitter. The transmitter converts the second satellite messageincluding at least one of voice, data, fax and signaling signals into amodulated signal, and transmits the modulated signal to the antennasystem. The transmitter includes an amplifier, a first converter andassociated first frequency synthesizer, a modulator, an encoder,multiplexer, scrambler and frame formatter for at least one of voice,fax, and data. The receiver accepts the first satellite message from theantenna system and converts the first satellite message into at leastone of voice, data, fax and signaling signals, at least one of thevoice, data and fax signals routed to the user interface system. Thereceiver includes a second converter with an associated second frequencysynthesizer, a demodulator, a decoder, demultiplexer, descrambler andframe unformatter for at least one of voice, fax, and data. The mobilecommunication system also includes a logic and signaling system,operatively connected to the transceiver, controlling initialization ofthe mobile communication system, obtaining an assigned outboundsignaling channel from which updated system information and commands andmessages are received. The logic and signaling system configures thetransceiver for reception and transmission of at least one of voice,data, fax and signaling messages, and controls protocols between themobile communication system and the mobile satellite system, andvalidating a received signalling messages and generating codes for asignaling message to be transmitted.

In one embodiment of the invention, a system for providing satellitecommunication between multiple users in a virtual network arrangementincludes first and second mobile earth terminals (METs) responsivelyconnected to and registering with the mobile satellite system. The firstMET selects a virtual network identifier (VN ID) representing a virtualnetwork group including the first and second METs to establish voicecommunication therewith and transmits the VN ID to a central controller.The central controller receives the VN ID from the first MET, allocatesa frequency for the virtual network group, and broadcasts the message tothe virtual network group including the second MET informing the virtualnetwork group of the allocated frequency and the voice communicationassociated therewith. The second MET tunes to the frequency in responseto the message broadcast by the central controller.

In another embodiment of the invention, a method of providing satellitecommunication between multiple users in a virtual network arrangementincludes the steps of first and second mobile earth terminals (METs)registering with the mobile satellite system, the first MET selecting avirtual network identifier (VN ID) representing a virtual network groupincluding the first and second METs to establish voice communicationtherewith. The method also includes the steps of the first METtransmitting the VN ID to the central controller, the central controllerreceiving the VN ID, allocating a frequency for the virtual networkgroup, and broadcasting the message to the virtual network groupincluding the second MET informing the virtual network group of theallocated frequency and the voice communication associated therewith.The method also includes the steps of the second MET tuning to thefrequency in response to the message broadcast by the centralcontroller.

In another embodiment of the invention, the method also includes thesteps of a third MET included in the virtual network group registeringwith the mobile satellite system, and the central controllerbroadcasting the message to the virtual network group including thethird MET informing the virtual network group of the allocated frequencyand the voice communication associated therewith. The method alsoincludes the steps of the third MET tuning to the frequency in responseto the message broadcast by the central controller.

According to the invention, the central controller advantageouslycontrols the virtual network satellite communication including virtualnetwork parameters used by the first and second METs.

The central controller advantageously collects billing informationregarding the virtual network satellite communication and transmits thebilling information to the mobile satellite system. The mobile satellitesystem optionally charges a service fee to a customer that has requestedthe virtual network arrangement instead of each of the individual usersin the virtual network group thereby consolidating the billingtransactions and permitting a single customer to monitor communicationcharges.

In another embodiment of the invention, the method includes the steps ofthe first MET selecting the virtual network identifier (VN ID)representing a virtual network group including the first MET and anon-MET serviced by one of a public switched telephone network and acellular network to establish voice communication therewith, and thefirst MET transmitting the VN ID to the central controller.Additionally, the method includes the central controller receiving theVN ID, determining that the virtual network group includes the non-MET,and broadcasting a non-MET message to either the public switchedtelephone network or the cellular network including the voicecommunication associated therewith, and either the public switchedtelephone network or the cellular network receiving the non-MET messagefrom the central controller and transmitting the non-MET message to thenon-MET to establish the virtual network arrangement between the MET andthe non-MET.

In another embodiment of the invention, the NOC manages and controls theresources of the satellite network system and carries out theadministrative functions associated with the management of the totalsatellite network system. The NOC communicates with the various internaland external entities via a local area network (LAN)/wide area network(WAN) based satellite network Internetwork and dial-up lines.

The NOC's network management functions include measuring the usage ofresources by customers to enable predictions of what changes to make inthe future deployment of resources. Such resources may be networkelements and CPUs in the system. Data such as usage records arecollected and analysis of capacity planning is performed based onpresent characteristics. Security functions are provided wherein thenetwork is protected against unauthorized use. Security mechanisms builtin to the network management include enhanced fraud security codingencryption and user passwords. Configuration management, i.e., howresources are allocated, is another function of the NOC. Fault detectionand management are provided for by the NOC. Problems are isolated andreported to operations personnel who can react to the problems.

In another embodiment of the invention, a method of performing a callsetup procedure in a mobile satellite system from a call initiated by amobile communication system (MCS) to a destination served by a publicswitched telephone network, includes the steps of initiating the call bythe MCS, the MCS formatting and transmitting an access request messagevia a random access channel, and receiving by the central controller theaccess request message, and transmitting frequency assignments to theMCS and to the SCSO. The method also includes receiving by the MCS thefrequency assignment, transmitting a scrambling vector message to theSCSO, and verifying by the SCSO the identity of the MET responsive tothe scrambling vector. Upon successful verification, the method includesthe steps of switching by the SCSO and the MCS from call setup mode tovoice mode, transmitting by the SCSO voices frames to the MCS includinga voice activation disable signal to disable a voice activation timer inthe MCS for at least 3 super frames, and transmitting a destinationnumber to the PSTN. The method also includes the steps of transmittingby the SCSO an enable signal to the MCS to re-enable the call activationtimer in the MCS, and establishing voice communication between the PSTNand the MCS.

In another embodiment of the invention, a method of performing a callsetup procedure in a mobile satellite system from a call initiated by adestination served by a public switched telephone network (PSTN) to amobile communication system (MCS). The method includes the steps ofreceiving by the SCSO a call from the destination served by the PSTN,transmitting by the SCSO to the central controller a channel requestusing interstation signaling, determining by the central controller anidentity of the MCS responsive to the destination number, andtransmitting a call announcement via a random access channel. The methodalso includes the steps of acknowledging by the MCS the callannouncement via the random access channel to the central controller,transmitting frequency assignments to the MCS via the random accesschannel and to the SCSO via an interstation signaling channel, andtransmitting an access security check field used to verify the MCS'sidentity. The method also includes the steps of receiving by the MCS thefrequency assignment, and transmitting a scrambling vector message tothe SCSO, verifying by the SCSO the identity of the MET responsive tothe scrambling vector, and upon successful verification, transmitting bythe SCSO a ring command to the MCS. The method also includes the stepsof receiving by the MCS of the ring command, generating a ringing signalto a MET user, and transmitting a ring command acknowledgement to theSCSO. The method also includes the steps of receiving by the SCSO thering command acknowledgement from the MCS, and once the call setup iscomplete, transmitting by the MCS voice frames to the SCSO including avoice activation disable signal to disable a voice activation timer inthe MCS for at least 3 super frames. The method further includes thesteps of upon detection of the MCS switching to a voice frame mode,switching by the SCSO to the voice mode, and transmitting a voiceactivation enable signal to the MCS to re-enable the call activationtimer in the MCS, and establishing voice communication between the PSTNand the MCS.

These, together with other objects and advantages which will besubsequently apparent, reside in the details of construction andoperation as more fully herein described and claimed, with referencebeing had to the accompanying drawings forming a part hereof whereinlike numerals refer to like elements throughout.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a diagram illustrating an overview of the satellite networksystem;

FIG. 2 is a diagram illustrating key performance parameters of thesatellite used in the satellite network system;

FIG. 3 is a diagram of the satellite network system illustratingcomponents and respective interfaces;

FIG. 4 is a diagram of a satellite network system illustrating a numberof system elements and their interconnecting communications links;

FIG. 5 is a basic block diagram of the NOC and its interfaces;

FIG. 6 is a basic block diagram of the physical architecture of themobile earth terminal;

FIG. 7 is a basic block diagram of the functions of the mobile earthterminal;

FIGS. 8a-8b are diagrams of the improved call setup protocol used toestablish a MET originated voice call;

FIGS. 9a-9b are diagrams of the improved protocol used for PSTNoriginated calls;

FIG. 10 is a block diagram of an improved NOC functional architecture;

FIGS. 11A-11C are diagrams of the NOC architecture in more detail;

FIG. 12 is a basic block diagram of the basic components of the NCCshowing the included GC;

FIG. 13 is a diagram of the NCC logical architecture;

FIG. 14 is a basic block diagram of a circuit switched NAP;

FIG. 15 is a block diagram showing the channel unit (CU) architecture;

FIG. 16 shows the GC subsystems which manage a call in progress;

FIG. 17 is an illustration of the basic role of the GWS within theMobile Satellite Services (MSS) system;

FIG. 18 depicts the basic call processing interaction between the GWSand other elements within and outside of the overall MSS system;

FIG. 19 is a functional illustration of the Gateway Switch;

FIG. 20 is an illustration of a virtual network associated with a groupof FESs and METs;

FIG. 21 illustrates the basic concept and elements involved inestablishment of communications and control in the virtual networksystem;

FIG. 22 illustrates an example of a virtual network service subscribingorganization with several communication virtual networks;

FIG. 23 is a decision tree of the order of application of the virtualnetwork rules; and

FIG. 24 is a more detailed illustration of the NCC terminal equipment.

BEST MODE FOR CARRYING OUT THE INVENTION

The present invention provides point-to-multipoint circuit switchedconnections between mobile terminal subscriber stations and a centralbase station. Mobile users are able to listen to two-way conversationsand to transmit.

The MET includes all of the communication and control functionsnecessary to support communications from a vehicle or fixed remote siteusing the resources of the satellite network system. FIGS. 6 and 7 arebasic block diagrams of the physical architecture and functions of themobile earth terminal. The basic functional diagram of FIG. 7 isimplemented by baseband processing and RF electronics of FIG. 6. Astandard voice coder/decoder receives coded messages from the basebandprocessing and RF electronic system and decodes the message receivedfrom the satellite antenna unit for delivery to the interface unit thatincludes standard user interfaces. Baseband processing and RFelectronics receive satellite communications responsive with low noiseamplifier (LNA) and output signals for transmission using the diplexerof the antenna unit. Baseband processing and RF electronics also outputssignals for use with beam steering antennas as will be discussed blow.Advantageously, the mobile earth terminal is functional with antennasthat are either steerable or nonsteerable.

The functional subsystems comprising the MET are shown in FIG. 7 andinclude the user interface, transceiver, antenna, logic and signaling,power supply subsystems, and Position Determination subsystem. Thebaseline MET will have a low gain directional antenna in the antennasubsystem. The satellite network system supports communications withMETs using omnidirectional and higher gain directional antennas.

The user interface subsystem provides the user interfaces through whichthe user has access to the services supported by the satellite networksystem. Depending on the service(s) the MET will be equipped with one ormore of the devices or ports. The transceiver subsystem consists of areceiver and a transmitter. The transmitter accepts voice, data, fax andsignaling signals and converts them to a modulated RF signal. Thetransmit RF signal is routed to the antenna subsystem. The transmittertypically consists of the high power amplifier (HPA), the upconverterwith its associated frequency synthesizer, the modulators and themodules for voice, Fax, or data encoding, multiplexing, scrambling, FECencoding, interleaving and frame formatting.

The receiver accepts modulated RF signals from the antenna subsystem andconverts them into voice, data, fax or signaling signals as appropriate.The voice, data and fax signals are routed to the user interfacesubsystem. The receiver typically consists of the downconverter with itsassociated frequency synthesizer, the demodulator, and the modules forframe de-formatting, de-interleaving, FEC decoding, descrambling,demultiplexing and voice, Fax, or data decoding. The transceivercommunicates over one channel in each direction at any one time. Thus,the transceiver subsystem will typically consist of only one receiverand one transmitter. However, the MET may also incorporate a pilotreceiver for antennas and frequency tracking purposes, or a completereceiver dedicated to the continuous reception of the signaling channelfrom the Group Controller.

The antenna subsystem provides the MET interface to the satellitenetwork and is responsible for receiving the RF signal from thesatellite and transmitting the RF signal generated by the MET towardsthe satellite. The subsystem typically includes an antenna which may beeither directional or omnidirectional, a diplexer, a low noise amplifier(LNA), an optional beam steering unit (BSU) if a directional antenna isused, a device such as a compass or an inertial sensor for thedetermination of the orientation of the vehicle, and an antenna for theposition determination receiver.

The logic and signaling subsystem acts as the central controller for theMET. Its basic functions are to initialize the MET by performing a selftest at power up and control, based on a resident system table, theacquisition of one of the METs assigned outbound signaling channels fromwhich updated system information and commands and messages from the GCare derived. The logic and signaling subsystem sets up and configuresthe transceiver for the reception and transmission of voice, data, faxor signaling messages as appropriate. The logic and signaling subsystemalso handles the protocols between the MET and the FES and between theMET the GC via signaling messages, and checks the validity of thereceived signaling messages (Cyclic Redundance Check (CRC)) andgenerates the CRC codes for the signaling message transmitted by theMET.

The logic and signaling subsystem also interprets the commands receivedfrom the local user via the user interface subsystem (e.g. on/off hook,dialled numbers, etc.) and take the appropriate actions needed, andgenerates, or commands the generation, of control signals, messages andindications to the user through the user interface subsystem. The logicsignaling system also controls the beam steering unit (if any) in theantenna subsystem, and monitors and tests all the other subsystems. Incase of fault detection, it informs the user about the failure and takethe appropriate measures needed to prevent harmful interference to thesatellite network or other systems.

The power supply subsystem provides power to all other subsystems. Theexternal voltage source to which this subsystem interfaces depends onthe type of vehicle on which the MET is mounted (e.g. 12/24 Volts DC forland vehicles).

A standard receiver such as a GPS or a Loran-C receiver is also providedfor the determination of the position of the vehicle. This informationis used by the logic and signaling subsystem for beam steering (if used)or for applications such as position reporting. The positiondetermination system is implemented externally to the MET and interfacedthrough a dedicated data port in the user interface subsystem.

The function of the Remote Monitor System is to continuously monitor theactivity on each GC-S channel and to monitor the activity within thedownlink L-band spectrum in the beam in which it is located. An RMS willbe located in every beam carrying satellite network traffic. An RMS maybe a stand alone station or collocated with the NCC or an FES. The RMSis controlled by the NOC and communicates via leased lines or theinterstation signaling channels if collocated with an FES. The RMSdetects anomalous conditions such as loss of signal, loss of frame sync,excessive BER, etc. on the GC-S channels and generates alarm reportswhich are transmitted to the NOC via the leased line interface. Inaddition, it monitors BER on any channel and power and frequency in anyband as instructed by the NOC.

The primary functions of the System Test Stations (STS) is to providecommission testing capability for every channel unit in a FES and toprovide readiness testing for the Off-Line NCC. The STS is collocatedwith and controlled by the NOC and will comprise one or morespecifically instrumented METs. The STS provides a PSTN dial-up port formaking terrestrial connections to FESs to perform MET to terrestrialend-to-end testing. The STS also provides a LAN interconnection to theNOC to provide access to operator consoles and peripheral equipment.

The MSS signaling system provides the communications capability betweennetwork elements required to set up and release communications circuits,provide additional enhanced services, and support certain networkmanagement functions. The network elements discussed above include groupcontrollers (GCs), feederlink earth stations (FESs), and mobile earthterminals (METs). The seven different channel types are:

    ______________________________________                                        GC-S   Outbound TDM signaling channel from the GC to the                             METs.                                                                  MET-ST Inbound TDMA signaling channel from the MET to the GC.                 MET-SR Inbound random access signaling channel from the MET                          to the GC.                                                             FES-C  Outbound communications and inband signaling channel                          from a FES to a MET.                                                   MET-C  Inbound communications and inband signaling channel                           from a MET to a FES.                                                   GC-I   Interstation signaling channel from the GC to an FES.                  FES-I  Interstation signaling channel from an FES to the                      ______________________________________                                               GC.                                                                

The basic element of communication for signaling and control for the MSSsignaling system is the Signaling Unit (SU). The SU consists of 96 bitsorganized in 12 octets of 8 bits each. The first 80 bits comprise themessage, and the last 16 a parity check, computed using the CCITT CRC-16algorithm. For transmission, the SU is convolutionally encoded at eitherrate 3/4 or 1/2, adding an additional 32 or 96 bits respectively.

The various fields are as follows:

Message type: A 7 bit code which identifies the meaning of the SU; inthis case a request for access to the MSS system for call placement.

MET-GC Signaling Protocol (MGSP) Header: A 8 bit field comprised ofseveral sub-fields giving particular information related to theprotocol: message type (command, response, message), message referenceidentification, and the number of times the message has beenretransmitted.

RTIN: Reverse Terminal Identification Number--the MET's ElectronicSerial Number, by which it identifies itself in transmissions on theMET-SR channel.

Digits 1-10: The first 10 digits of the addressed telephone number inthe PSTN or private network, in hexadecimal. If the 10th digit is set to"C", an address of greater than 10 digits is indicated.

CRC: The 16-bit error detection code (Cyclic Redundancy Code).

The frame formats used in the GC-S, MET-SR and MET-ST channels areclosely related, and are based on a common 360 millisecond superframeestablished on the GC-S channel. All timing relationships in the MSSsystem signaling scheme are determined from the GC-S frame structure.The GC-S is operated in the QPSK mode at an aggregate rate of 6750 b/s.The stream is divided into superframes of 360 ms, comprising three 120ms frames. Each frame is in turn comprised of a 24-bit unique word (UW),six SUs, eight flush bits and 10 unused bits, for a total of 810 bitsand 120 ms. The first frame of a superframe is identified by inversionof the UW.

Mobile terminals throughout the area covered by any beam receive GC-Schannels with a total uncertainty of approximately 32 ms, primarily dueto their geographical locations. The received superframe boundaryestablishes the four 90 ms "slots" in the MET-SR random access channels,which operate in the BPSK mode at 3375 b/s. The actual random accessburst is comprised of a 24-bit preamble, a 32-bit UW, a 128-bit SU (96bits rate 3/4 coded), and eight flush bits, for a total of 192 bits in56.9 ms. This allows a 33.1 ms guard time between bursts. MobileTerminals select a MET-SR channel and slot at random from among thepermitted choices.

The MET-ST TDMA channels, which also operate in the BPSK mode at 3375b/s, are comprised of bursts which are equal in length to the GC-Sframe, and which are also timed on the received frame boundary. The TDMAburst is made up of a 24-bit preamble, a 32-bit UW, a 192-bit SU (96bits rate 1/2 coded), and eight flush bits. The total length of the TDMAburst is 256 bits in 75.9 ms, which allows a guard time of 44.1 ms.Mobile Terminals always respond to commands received on the GC-S on aMET-ST channel which corresponds in number to the position of thecommand SU in the TDM frame. For example, the MET will respond to acommand in SU slot 2 on MET-ST channel 2, and so forth. The response isalways transmitted in the second frame time after receipt of thecommand, so that there is a minimum of 120 ms in which the MET canprepare its response.

The initial phase of establishing a call is handled by out-of-bandsignaling on the GC-S, MET-SR and MET-ST channels. This phase culminatesin assignment of a pair of communication channels to the MET and FES.When these elements receive and tune to the communication channels,further signaling and control functions are accomplished using inbandsignaling. The communication channels, FES-C and MET-C, use a variety ofrelated TDM formats which are determined by the intended use of thelink, i.e., voice, data, or facsimile and one of three possible primarymodes: call setup (entirely signaling), communication (no signaling), orin-band signaling (an occasional subframe of 128 bits is used forsignaling/control).

The same 96-bit SU described above is used to accomplish in-bandsignaling. The outbound TDM, inbound TDMA, and inbound random accesschannels provide signaling between the GC and each of the METS in theassociated control group. All communications on these channels will bepassed in the form of 96 bit (12 octet) messages known as signalingunits. Each signaling unit will begin with a 1-octet messages type fieldand end with a two-octet cyclic redundancy check. The MET to GCSignaling Protocol (MGSP) serves as the layer two protocol for thesechannels.

Communications from the group controller (GC) to the mobile terminals isprovided by the Outbound TDM or GC-S channel. The primary function ofthis channel is to carry frequency assignments from the GC to individualMETs. In addition, the Outbound TDM channel carries network statusinformation which is received by all METs in a particular beam andcontrol group. The outbound TDM channel operates at a rate of 6750bits/s with rate 3/4 FEC. QPSK modulation and nominally 6.5 kHz channelspacing (other spacings are under investigation) is employed. Theseparameters are identical to those of the communications channel and werechosen to reduce MET complexity.

Inbound TDMA (MET-ST) channels are used by the MET to respond to actionsinitiated by the GC, such as responding to the call announcement issuedby the GC to check a MET's availability to receive a PSTN originated orMET to MET call. The Inbound Random Access (MET-SR) channels are used byMETs to request frequency assignments and for other MET initiatedactions. The inbound random access and TDMA channels each operate at arate of 2400 bits/s with rate 3/4 FEC. DPS modulation and nominally 7.5kHz channel spacing is employed. This modulation scheme has beenselected because of its robust performance in the presence of frequencyoffset and timing errors, it also exhibits superior performance relativeto conventional BPSK in the presence of band-limiting and hard-limiting.

Each control group has associated with it a number of L-band beams overwhich it operates. In each of these L-band beams a control group hasassociated with it a distinct set of outbound TDM, inbound TDMA, andinbound random access channels. The number of signaling channels of eachtype in each set is determined based on the level of signaling trafficflowing between the GC and the METs in that control group in that L-bandbeam. As signaling traffic levels change, new signaling channels of eachtype are allocated to or deallocated from a particular set of channels.The frequencies used for outbound TDM, inbound TDMA, and inbound randomaccess channels are included in the status information carrier in thebulletin board signaling units transmitted on the outbound TDM channel.

Each MET is assigned to one of the outbound TDM channels in the controlgroup and beam to which it belongs. Each control group supports up to 16outbound TDM channels in each beam. Each outbound TDM channel hasassociated with it up to 6 inbound TDMA channels. An inbound TDMAchannel will only carry messages that are responses to messages receivedon the outbound TDM channel with which it is associated inbound randomaccess channels will not associated with a particular outbound TDMchannel. A MET chooses a inbound random access channel at random fromamong those associated with its control group and beam each time amessage is to be transmitted. Each control group can support up to 64inbound random access channels in each beam. Up to 64 of these channelsmay be used system wide to meet the signaling requirements of a fullyloaded system supporting 5000 circuits.

Inband signaling channels (FES-C and MET-C) are provided between the FESand the MET. These channels are used to provide signaling for call setupand call release, and also provide the capability to pass othersignaling information while a call is in progress. The FES-C and MET-Cchannels are operated in two separate modes in "call setup mode" onlysignaling messages are carried by the channel. In voice mode voiceframes are carried by the channel, but the capability to injectsignaling messages by occasionally dropping voice subframes exists.Frames containing inband signaling messages employ a unique worddifferent from that used for frames containing only voice subframes.

Interstation signaling channels (GC-I and FES-I) are used to passsignaling information between the GC and each of the FESs. Thesechannels operate at a rate of 9.6 to 64 kbit/s and are implemented usingeither the available 5 MHz Ku-band satellite capacity or terrestriallinks. The LAP-F protocol will be employed on those links to ensurereliable transfer of variable length signaling and network managementmessages.

When a MET is idle (powered on and ready to receive a call) it willcontinuously receive an Outbound TDM channel in order to receive callannouncements associated with incoming calls and obtain statusinformation from bulletin board signaling units. Each MET will becapable of transmitting signaling information to the GC on any of theinbound random access channels or on any of the inbound TDMA channelsassociated with the outbound TDM channel that it is receiving. During acall a MET will receive and transmit all signaling information via theIn-Band signaling channels. No signaling information will be sent to aMET via the outbound TDM channel during a call. Any signaling messagesfrom the GC to the MET will be sent to the MET via the FES through theGC-I and FES-C channels.

Each group controller supports at least one outbound TDM channel in eachof its associated L-band beams. Each outbound TDM signaling channel iscontinuously transmitted and carries frequency assignments and networksstatus information from the GC to the METs. The outbound TDM channelsare also used to poll idle METs to see if they can accept incomingcalls. As this channel is the only way to signal information to a METnot engaged in communications, it must be as robust as possible underharsh fading and shadowing conditions.

Another key element in the MSS system is the need for the METs to be asinexpensive as possible. Towards this end, the outbound TDM channel willhave the same rate and modulation as the communications channels. Thiswill maximize the commonality of the receive chain of the MET forcommunications and signaling. Note that as the demodulation process ismuch more complex than the modulation process, the inbound random accessand inbound TDMA channels do not really require this level ofcommonality with the communications channel.

The number of outbound TDM channels assigned to each set of signalingchannels is determined by the traffic supported by the group controllerin that L-band beam. Assignment of METs to outbound TDM channels is madebased on a special identifier assigned to each MET as commissioning.This identifier is called the GC-S Selector Identifier code (GSI). TheMET selects the outbound TDM channel to be used by dividing the GSI bythe total number of outbound TDM channels available in the given beam.The number of TDM channels available is given in the BB of each TDMchannel. The remainder of the four bit binary division process will formthe number of the channel to be used. Each MET will receive only theoutbound TDM channel assigned to it. This method allows METs in the samelogical grouping to be assigned to the same outbound TDM channel as isneeded for the Virtual Network Service provided by the MSS System. Italso allows the load on the outbound TDM channels to be redistributedquickly if a channel fails or a new channel is added.

The 120 ms frame length was chosen because it would support 6 messagesper frame and correspond to the slot size requirement (>120 ms) of theinbound TDMA channel. This allows a direct correspondence betweenoutbound TDM frames and inbound TDMA slots for the purposes of TDMAsynchronization and scheduling responses to outbound messages. Eightflush bits are included at the end of each frame to allow the decoder toreset to a known state at the beginning of each frame. This allows morerapid reacquisition following channel fade events. The modulation schemeand transmission rate for this channel will be the same as for thetransmission channel, namely QPSK modulation at a transmission rate of6750 bps. Signaling units within each frame will be coded with a rate3/4 constraint length K=7 convolutional code.

The outbound TDM superframe has a duration of 360 ms and is made up ofthree outbound TDM frames. The superframe duration is the basic timeinterval over which message repetitions are done. Repetitions are usedto increase the reliability of outbound TDM signaling units. Messagescan be repeated in consecutive superframes. Studies by AUSSAT have shownthat L-band fade events typically have durations ranging between 10 msand 100 ms (2). Because the 120 ms frame would not provide adequateseparation between message repetitions, the 360 ms superframe is used toreduce the chance of losing two copies of a message during the sameL-band fade event. This repetition method is similar to that used in theAUSSAT system. Different numbers of repetitions may be used fordifferent message types to provide different levels of reliability. Thenumber of repetitions used for a particular message type will be a partof the signaling protocols and can be varied by the system operator. Inaddition to message repetitions, interleaving will be used to protectagainst burst errors. The interleaving is provided over a TDM frame andprovides improved performance in the presence of short burst errors.

The bulletin board is a set of signaling unit (SUs) that areperiodically transmitted by the MCC on all outbound TDM channels. Thebulletin board contains global information such as current networkstatus, signaling channel frequencies and inbound random access channelcongestion control parameters. Every MET processes the information inthe bulletin board METs, on startup, and acquires the entire bulletinboard before attempting to use the MSS system. At least one bulletinboard SU is transmitted in every outbound TDM frame. Bulletin board SUsare also sent as "filler" SUs, i.e., sent when there are no other SUspending on the outbound TDM channels. Bulletin board SUs do not occupyany fixed position in the outbound TDM frame.

Bulletin board SUs are grouped into pages of related SUs. Each BulletinBoard page has an update number associated with it, which will be sentwith each SU of that page. This number will be incremented by the NCCwhenever the information in that page is updated. METs are required tobuild a local data structure that contains the contents of the bulletinboard. Whenever a change in update number is detected for any page, theMET will update the entire data structure for that page with thecontents of the bulletin board SUs that follow.

The inbound TDMA channel is used by the METs to transmit responses tocall announcement messages and for responses to other messages receivedon the outboard TDM channel. Each of the inbound TDMA channels isassigned to a particular outbound TDM channel. The number of inboundTDMA channel assigned to a particular outbound TDM channel depends onthe traffic supported by that outbound TDM channel and is selectable bythe network operator. The TDMA channel is divided into slots of 120 msduration. Inbound messages consist of 96 bits before coding and 128 bitsafter rate 3/4 convolutional coding. The resulting burst will occupy 80ms of the slot, allowing 40 ms of guard time.

This guard time arises due to the uncertainty in round trip transmissiontime between the satellite and a mobile terminal. Mobile terminalsderive their inbound frame timing (for both the TDMA and random accesschannels) from the outbound TDM frames. Inbound TDMA slots have the sameduration as an outbound TDM frame. At a MET each TDMA slot boundaryoccurs at an outbound TDM frame boundary. If MET A is nearer to thesatellite than MET B, MET A will receive the outbound TDM channel Δtsooner than MET B, where Δt corresponds to the difference in propagationtimes to the satellite for the two terminals. As a result, if both METssynchronize their transmit timing to their reception of the outbound TDMchannel, MET B's responses to messages will take 2Δt longer to reach thesatellite than MET A's responses. As additional guard time of 1 symboltime also must be included to account for the ±1/2 symbolsynchronization uncertainty in the MET. This results in a total guardtime requirement of 2Δt+1 symbol time.

TDMA scheduling is done using a fixed relationship between outbound TDMchannel time slots and inbound TDMA channels and slots. The response toa message received in the nth slot of the outbound TDM frame istransmitted on the nth TDMA channel assigned to that outbound TDMchannel. The frequencies of the assigned inbound TDMA channels arecontained in one of the bulletin board signaling units periodicallytransmitted in the outbound TDM channel. The response to an outboundmessage is transmitted in the TDMA time slot that begins 120 ms afterthe end of the TDM frame in which the outbound message was received.This should provide adequate time for message processing in the MET.

The inbound random access channel is used by the METs to transmit callrequests to the GC. It is also used to carry other inbound messages forMET originated actions. The number of inbound random access channelsassigned to a particular control group in a particular L-band beamdepends on the traffic supported by that control group in that beam andis selectable by the network operator. To provide reasonable call setuptimes and call loss probabilities these channels are typically beoperated at a throughput of approximately 25% or less. As the randomaccess channel is operating at a relatively low efficiency, one of theprime goals in its design is that it be bandwidth efficient.

The frequencies used for the random access channels are transmitted inthe bulletin board signal units. For each transmission, METs choose atrandom among the inbound signaling channels assigned to their controlgroup. After transmitting a message, the MET waits a given amount oftime for a response. If no response is received within this amount oftime, the MET retransmits in a slot selected at random over some givennumber of slots. This procedure is repeated until either a response isreceived or a maximum number of transmissions is reached. The bursts onthe random access channel are identical to those on the TDMA channel(i.e., modulation, coding, preamble, etc.).

The MET-GC Signaling Protocol (MGSP) procedures send signaling unitsbetween GCs and METs via the GC-S, MET-ST and MET-SR channels. Thisprotocol encapsulates functions such as channel selection, channelaccess, slot timing, error recovery and congestion control. Higher layerfunctions, such as call processing, use the protocol for communicatingamong themselves between the METs and GCs.

A transaction consists of a command message that is sent from anoriginating application to a destination application, to which thedestination application replies with a response message. Each commandand response consists of a signaling unit. The MGSP performs functionssuch as channel selection, error recovery using retransmission, andrepetition of SUs to improve channel reliability. The MGSP at a MET alsoimplements congestion control procedures for the MET-SR channels. Onlyone outstanding transaction exists between a MET and a GC in a givendirection. However, two simultaneous transactions, one in eachdirection, are supported between a GC and a MET. MGSP also provides aonly-way message service, that does not require a response from thereceiver.

The improved call setup protocol used to establish a MET originatedvoice call is shown in FIGS. 8a-8b. When a MET user initiates a call,the MET formats and transmits an access request message via a randomaccess channel. This message includes the call type and the destinationphone number. The group controller chooses an FES to handle the call andsends frequency assignments to the MET via the TDM channel and to theFES via the interstation signaling channel. The FES frequency assignmentalso includes the call type, the destination phone number to allow theFES to complete the call, and an access security check field used toverify the METs identity. The access security check field is generatedby the group controller using the MET frequency assignment and the METkey which is known only to the MET and the group controller.

After the MET receives the frequency assignment, it transmits ascrambling vector message to the FES. This message contains the initialvector to be preloaded into the FES scrambler at the beginning of eachvoice channel frame. Letting the MET randomly pick this vector providessome degree of privacy on the Ku to L-band link. The scrambling vectormessage also contains an access security check field generated by theMET using its frequency assignment and its key. The FES compares thisfield with that received from the group controller to verify theidentity of the MET. When the FES receives the scrambling vector, theFES will check the validity of the METs identity. If the check fails,the FES will initiate a call release.

After receiving the scrambling vector message and successfulauthentication of the MET (see U.S. application Ser. No. 08/565,036,filed Nov. 30, 1995, entitled FRAUD DETECTION AND USER VALIDATION SYSTEMFOR MOBILE EARTH TERMINAL COMMUNICATION DEVICE," incorporated herein byreference), the FES and the MET switch from call setup mode to voiceframe mode and the FES completes the call to the terrestrial networkuser. The FES transmits voices frames to the MET to effectuate voicecommunication. We have discovered that the coder/decoder which is usedin the MET imposes certain constraints described below that require thesignalling architecture to be adapted thereto.

Specifically, it has been determined that the voice coder/decoderperforms the following functions that impact on the signallingarchitecture in the context of our mobile satellite system. The voicecoder/decoder receives coded messages from the baseband processing andRF electronic system and decodes the message received from the satelliteantenna unit for delivery to the interface unit that includes standarduser interfaces. The voice coder/decoder processes speech to produce6400 bps output. The inherent speech coding rate is 4150 bps, to which2250 bps of error correction and detection is added. The coder/decoderencodes 160+/-4 samples of speech and converts it to 128 bits. Theencoding function is called approximately every 20 ms to produce the6400 bps bit stream. The coder/decoder decodes 128 bits of speech andproduces 160+/-4 samples of speech. The encoder/decoder also performsvoice activity detection.

In accordance with the coder/decoder functions and operations, thecoder/decoder includes a voice activation timer or synchronizer that isused to determine and insure that a caller is present during the callsetup process. The encoder determines that the voice communication isactive when valid data appears at the output within two sub-frames orapproximately 40 ms. The encoder determines that the voice communicationis not active when no voice activity occurs for 3 sub-frames orapproximately 60 ms. The decoder sets the voice activity to active whenvoice activity is detected, and to inactive when no voice activity isdetected.

In accordance with the above constraints of the coder/decoder, it hasbeen determined that the protocol used by the mobile satellite systemmust be adapted for use with the standard encoder/decoder used for voicecommunication. In particular, it has been determined that the inherentdelays in the mobile satellite system are incompatible with the voiceactivation timer used in the coder/decoder. In this connection, it hasbeen determined that it is beneficial to eliminate usage of the voiceactivity timer during the voice mode prior to completion of call setup.Once call setup has been completed, the voice activity timer can then bere-enabled and used for its intended purpose, i.e., to determine whetherthe call is still active or whether the call has terminated, therebyfreeing up satellite resources more expediently.

Accordingly, once voice frames have been transmitted from the FES to theMET in the voice mode, and once the FES transmits the destination numberto the PSTN, the FES also transmits a voice activation disable signal tothe MET to disable the voice activation timer in the MET. The voiceactivation timer is then disabled for at least 3 super frames. After theFES has completed call setup with the GC, the FES transmits a signal tore-enable the call activation timer in the MET.

The PSTN provides ringing tones to the FES indicating that the call isbeing placed to the destination, and the FES in turn transmits theringing tones to the MET. When the destination telephone answers the METoriginated call, an off-hook signal is transmitted from the PSTN to theFES, and the FES in turn transmits same to the MET indicating that thecall has been answered by a user connected to the PSTN. Voicecommunication between the MET and the PSTN destination via the FES isthen commenced until either party terminates the MET originated call.

The improved protocol used for PSTN originated calls is shown in FIGS.9a-9b. When a call from a terrestrial network user arrives at an FES,the FES makes a channel request using interstation signaling. Thisrequest contains the phone number received from the terrestrial networkuser. The group controller determines the MET identity based on thephone number and transmits a call announcement via the TDM channel. TheMET acknowledges this announcement via the TDMA channel. This exchangeallows the group controller to verify that the MET is available beforeassigning bandwidth to the call. Frequency assignments are then made andthe scrambling vector is transmitted by the MET once the MET tunes tothe assigned frequency.

Upon successful reception of the scrambling vector, the FES checks thevalidity of the MET's identity. If the check fails, the FES initiates acall release procedure. If not, the FES transmits the ring command tothe MET. Upon reception of the ring command by the MET from the FES, theMET generates a ringing signal to the MET user and transmits a ringcommand acknowledgement. The ring command acknowledgement is repeated bythe MET until the MET is taken off-hook by the MET user or until thecall is cleared. Upon receipt of the acknowledgement from the MET andonce the call setup is complete, the MET begins transmitting voiceframes to the FES and also transmits a voice activation disable signalas described in connection with MET originated call setup procedure.Once the MET is taken offhook the MET switches to the voice frame mode.Upon detection of the MET switching to the voice frame mode, the FESstops transmitting null signal units, switches to the voice mode,transmits a voice activation enable signal and commences voicecommunication between the MET and PSTN.

MET to MET calls are set up using a double hop connection through anFES. These calls are set up by the group controller and the FES as a METto PSTN call setup concatenated with a PSTN to MET call setup. As aresult the METs require no additional call processing for MET to METcalls. That is, the procedures at the MET for receiving a MET-MET callare the same as procedures for reception of PSTN-MET calls, and theprocedures at the MET for originating a MET-MET call are the same asprocedures for origination of MET-PSTN calls.

Advantageously, the MET combines three different features for thedelivery and transmission of voice and data. These three featuresinclude: the ability to initiate and transmit a data call, the abilityto initiate and transmit a facsimile digital call, and the ability toroam between satellite and terrestrial based wireless communicationsystems. The following documents, representing applicable transmissionprotocols, are hereby incorporated by reference: EIA/IS-41B CellularRadio Telecommunications Inter-System Operations; EIA/TIA-553-1989"Cellular System Mobile Station--Land Station Compatibility Standard";EIA/TIA-557; EIA/IS-54B.

The improved NOC functional architecture is shown in the block diagramof FIG. 10. The NOC collects information pertaining to the utilizationof resources and distributes information to appropriate destinationssuch as CMIS and NE/SE. The NOC is involved in network security toprevent unauthorized use. The blocks shown in the figure broadlyrepresent the functions that the NOC performs or oversees. The networkmanagement is a framework for the NOC basic functions. The configurationmanagement implements and allocates resources in cooperation with plansformulated with NE/SE. The operator interface serves a fault managementfunction. Problems in the system are isolated and reported to giveoperations personnel the ability to see when problems occur and react tothem. The operator interface is a man-machine interface (MMI) to presentalarms and events to the operators. Information as to systemconfiguration is also made available. Call records management serves asan accounting functionality. This function accepts MET registrationrecords and other information sent by external entities for storage inappropriate NOC database tables. Usage data sent by the individual GCsand FESs are assembled into Call Records. Data management serves as adata base repository for transmission and receipt of informationgathered by the other components of the network operations center.

FIGS. 11A-11C set forth the NOC architecture in more detail, theelements shown corresponding to the blocks of FIG. 10. As shown in FIG.11A, the network management block contains Polycenter Processes modulesthat serve alarm manager, exporter, historian and operator controlfunctions. The historian records performance of the network over time,collecting at suitable intervals statistics regarding resourceutilization, calls in progress. The management information repository(MIR) server interfaces with the exporter. Network update requests arereceived from the router. When transactions come in from NE/SE or CMIS,they need to be distributed to different parts of the system. Updatesare distributed to the MIR server so that it can update the internaldata base. After all elements of the system are set up, network updatesare communicated back to the router for network implementation. Exportertransmits collections of information, including performance trafficdata, to the database in the data management block. The NE/SE system isdescribed in detail in U.S. application Ser. No. 08/601,749 filed onFeb. 15, 1995, incorporated herein by reference. The CMIS system isdescribed in detail in U.S. application Ser. No. 08/598,556 filed onFeb. 8, 1996, incorporated herein by reference.

The alarm rule manager sets thresholds for adverse conditions andexecutes set up procedures for the event management block. For example,if customer service center sends out a commissioning request and thecommissioning fails, an alarm is generated and the NOC sends a messageto CMIS describing the failure and the cause of the failure. Thewatchdog looks for events, such as the system disk becoming fullyutilized and other fault conditions, and sends an alarm to NMS tooperator screen. The performance data collector samples resourceutilization, collects statistics and provides feedback. NOC processcontrol is involved with custom processes such as NOC startup andshutdown.

Configuration updates are received by the configuration managementblock, shown in FIG. 11A. A routing table is used to distribute messagesto the appropriate components of the NOC.

The data management block, illustrated in FIG. 11B, includes servers tointerface with the NOC main data base (DB). The RTR router receives RTRrequests from either satellite resource manager or configurationmanagement. The NOC configuration DB server decides from polling NOCcomponents whether the request for update is to be accepted. If so, theNOC data base (DB) is updated and confirmation is sent to othercomponents to update local data bases. The request is basicallydistributed to all other components to vote on the appropriateness ofthe requested change. For each transaction there is a specific set ofdata bases that are to be updated. DC Comm exports information from thedatabase to NE/SE and CMIS. As read transactions do not need to gothrough this voting to update process, accessing for reading is easilyavailable to any of the system components. Performance data, collectedin the network management collector, previously described, isperiodically exported directly to the data management DB, as no updatingof other module databases is needed. Such data is not related to theoverall configuration.

The call records management block is shown in FIG. 11C. Thefunctionality of this component accounts for customer usage to enablebilling preparation by the configuration management information system(CMIS). Call detail records (CDRs) relating nonsatellite usage arereceived from the gateway switch (GWS) and call performance records(CPRs), or call usage records (CURs), relating satellite usage arereceived from the group controller (GC). These records are logged intofiles at the GWS and CUR/NRPR servers to be forwarded to CMIS and savedas backup in the data base. The call trace router sends RTR requests forcall tracing and trapping to and from the GC. Call tracing requests aresent to the trace operator, shown in the operator interface block ofFIG. 11C. Call trace information is received by the call trace routerfrom the trace operator.

The operator interface includes the session manager. After logging in tothe session manager, each of the functions represented by the otherblocks within the operator interface block is available. When the systemis started or restarted, the encryption/decryption code is established.The MT ASK (Access Security Key) block, essentially a separate database, contains specific keys specific to each telephone and is checkedin real time for each call. The mobile telephone (MT) key is set up whenthe new MT is added to the system. MT ASK is also used for storing CMISand GC encryption keys used for encrypting request transactions. Theoperator message (Op. Msg.) block is an interface for E-mail. Resourceallocation MMI permits the NOC operator to modify the system for day today operations, such as taking resources off line or on line. The DBaccess permits the operator to read the data base DB. Bulletin Boardrecords containing transmit and receive frequency information about theMETs are available to the operator from the Site Manager location.

The event management block, involved with fault management, is shown inFIG. 11B. All messages are received in the event logger, logged to afile, sent to a printer and displayed at the NOC MMI. Where necessary,files are forwarded to external organizations such as CMIS or NE/SE. CGS(communications ground segment) event data are sent to the CGS eventsink. The COTS (Commercial off the shelf) software sink receives otherevents, such as VMS events. The watchdog event sink receives events fromthe watchdog block in the network management block, described above. Theoperator communication (OPCOM) generator converts VMS events into acommon format.

FIG. 12 illustrates the Network Communications Center (NCC) and theelements contained therein. The Group Controller (GC) resides in theNetwork Communications Center (NCC) system element within the CGS andprovides call control and satellite resource management for:

Circuit-switched voice, FAX, and data calls;

Integrated Voice and Data MT (IVDM) voice calls;

Satellite trunked radio calls.

The GC controls setup, monitoring, and cleardown of calls between MTs,IVDMs, VN MTs, and terrestrial users. It also provides AMS(R)SProvisioning, Control Group Reconfiguration, MT and FES PVT andCommissioning support, and Performance and Status Monitoring.

The primary function of the GC is the management of customer ControlGroups. Control Groups identify groups of MTs/IVDMs which have access toCGS, the satellite and network resources that have been allocated tothem for sending/receiving calls, and the service permissions andcalling restrictions that apply to each MT/IVDM. Control Groups alsocontain Virtual Networks (VNs) discussed below, which define the routingoptions that apply to each MT or IVDM in the Control Group and CircuitPools, which control the allocation of use of satellite circuits forcircuit-switched calls.

FIG. 13 illustrates the NCC logical architecture. The Group Controllerconsists of five top level components which perform the followingfunctions:

1. Call Management

This component performs:

Call setup/monitoring for:

a. MT-to-MT, MT-to-PSTN/PN, PSTN/PN-to-MT calls

b. MT initiated VN Calls

c. Dispatch initiated VN, Private Mode, Broadcast, and Priority 1 calls.

MT Management, including:

MT Logon, GC-S Change, MT Shutdown, and MT Parameter Update, VisitorRegistration;

Preemption of calls for AMS(R)S provisioning of satellite bandwidth andpower.

MT Commissioning and PVT.

2. Resource Management

This component performs resource management and reconfiguration,including:

allocation/deallocation of satellite resources during callsetup/cleardown

incremental/complete reconfiguration of local Control Group databases

address screening

MT authorization

call routing

Virtual Network configuration

3. Configuration Management

This component performs executive control for:

Control Group configurations;

AMS(R)S requests

4. MT ASK Management

This component performs:

secure MT ASK database management

real-time check field generated for call processing

ASK generation after completing commissioning/PVTs for Enhanced Fraud

5. Utilities

This component is the common utility set for the GC including:

MGSP

Call Record Management

Performance and Traffic Statistics generation

Congestion Control

Memory Management

X.25 interface.

The NCC provides real time call processing for users of the CGS byassigning resources on a per call basis. The NCC operates under theadministrative control of and is monitored by the NOC. The NCC managesaccess of users of the space resources allocated to the NCC by the NOC.The NCC provides system monitoring and testing functions to support FESand MT commissioning and periodic performance verification testing. Asingle NCC provides these functions for an entire network carrying thefull traffic load. In the event that the NOC is not available, the NCCcontains a backup operator interface capable of monitoring andcontrolling the ongoing provision of services to customers and which iscapable of providing emergency AMS(R)S provisioning.

Logically, the NCC is divided into two functional groupings, namely RFEand processing/management functions. Physically, the NCC is similarlydivided into RFE and terminal equipment which performs the processingand management functions. The NCC terminal equipment is composed of anintegrated set of hardware that is shared with the NOC and FES elements.From the NCC perspective, the hardware is composed of three sets ofequipment which include the Circuit Switched Management Processor(CSMP), Network Access Processors (NAPs), and Channel Units (CUs). TheNAP functions for the NCC consist of Network Access Processors forSignaling (NAP-S), Network Access Processors for Communications andTesting (NAP-C(Test)), and Bridges Modems for Interstation SignalingChannel Units. Both the NAP-S and NAP-C(Test) have channel unitsassociated with them. The NAPs, Bridges and Channel Units together formthe NAP-CU HWCI. There are two styles of NAPs, namely, the CircuitSwitched NAP and the Data NAP. The Circuit Switched NAP performs theout-of-band signaling (NAP-S) functions or communications (NAP-C)functions.

A block diagram of the circuit switched NAP is shown in FIG. 14. The NAPis PC-based and contains a processor card, and SDLC card forming theinterface with up to 24 channel units, an ethernet card providing theinterface to ethernet B in the CSMP, and a distribution card. Thedistribution card provides a DS-1 interface between the gateway or baseswitch in the FES and the communications channel units, and a frameclock distribution function between the RF equipment and the out-of-bandsignaling channel units. NAPs are used in pairs for redundancy with anon-line and an off-line NAP or NAPs A & B. Each NAP monitors thecondition of the other and takes over processing when a failure isdetected or by operator (NOC or backup NCC) command via the systemcommon software CSCI Site Manager function. The NAP-S and NAP-C connectto a channel unit of the same type which forms the interface to the RFEfor signaling and communications. The CUs are hardware identical andtake on their operational personality (S or C) with a software downloadwhen they are initialized.

A block diagram of the CU is shown in FIG. 15. The CUs are composed oftwo major sections: the Baseband Signal Processor Unit (BSPU) and theChannel Signal Processing Unit (CSPU). The CU interfaces to the NAP areshown on the left and the interfaces to the RFE are shown on the right.The sub-element processor types are noted in the diagram.

The BSPU is composed of three major functions: the SDLC Controller(Z80235), Monitor & Control (80186EC) and the voice/modulated dataprocessing (twin TMS320C31). The SDLC Controller provides the interfacebetween the main and redundant NAPs. The Monitor & Control functionprovides the central control and status focus. This processor alsosupports the software downloads to a given CUs set of processorsub-elements. The pair of TMS320C31 processors provide the functionalprocessing for echo cancellation, rate adapting and detection, mu-lawlinear decompression, CODEC, voice, voice modulated data, FAX.

The CSPU is composed of a DSP, I/Q channel A/Ds & D/As, L-Band transmitsynthesizer and L-Band receive synthesizer. The major functionsperformed by the DSP include data framing, encoding/decoding,interleaving, scrambling/descrambling. The DSP operates on digital datafrom the receive synthesizer A/Ds and supplies digital data to the D/Asfor transmission via the transmit synthesizer. As noted earlier, thereare up to 24 CUs controlled by a single NAP pair (i.e., main/redundant).

The NCC element is composed of a GC CSCI hosted on the CSMP, a NAP CSCIhosted on the NAP processor and the CU CSCI hosted on the set of CUprocessors as shown in FIG. 15. The NCC element also requires someportions of the SCS CSCI which is hosted on the CSMP. Both the NAP CSCIand the CU CSCI require a communications version and a signaling versionof these SCS CSCIs. Both versions execute on the same physical H/Wconfiguration type. The functions of the NCC element are implemented bya set of software processes as follows:

    ______________________________________                                        CSCI     Process       Major Function                                         ______________________________________                                        GC CSCI  Call          Call Processing                                                 Config        GC Database Configuration                                                     Management                                                      Monitor       Call record/statistics                                                        manager                                                         ASK Config    ASK Configuration Database                                                    manager                                                         Check Field   Check Field Generation                                          GC Router     GC message router                                               GC Router Config                                                                            GC router DB Configuration                                                    Manager                                                         Config Requester                                                                            Configuration access by call                                                  processing                                                      ASK Requester ASK database access SCS                                                       CSCI                                                            VAX, NAP message                                                                            Distribute NAP oriented                                                       messages                                                        VAX, VAX message                                                                            Distribute VAX to VAX                                                         messages                                                        Process Control                                                                             Monitors VAX processes                                          Site Manager (NR)                                                                           Non-real time network                                                         management                                                      Site Manager (R)                                                                            Real time network management                           NAP CSCI BB-PDU        Bulletin board processing                                       NAP-PM        Collect/report performance                                                    data                                                            NAP-I/O       Process I/O in and out of                                                     NAP                                                    CU CSCI  CU-CM         Perform MT PVT &                                                              commissioning tests                                             CU-SM         Perform signaling channel                                                     functions                                                       CU-LIB        Common CU support functions                            ______________________________________                                    

The SCS CSCI is primarily responsible for network management functions.Software and hardware objects are managed and status and events reportedto the NOC.

The NAP CSCI performs both call processing and network managementfunctions. Interaction with the GC is established for receiving the GC-Ssignaling units for transmission via the SCU to the MTs. The NAP alsoreturns to the GC the SUs received from MTs via the MT-SR and MT-STchannels.

The GC CSCI includes the following databases:

MT Database

MT Basic Data Table

MT VN Memberships Table

MINData Table

MT Restrictions Table

DN Data Table

MT VN Memberships Table

MT Class Table

Virtual Network Database

VN Data Table

Routing Lists Table

VN NPA Table

Circuit Pool Database

Circuit Pool Table

Freq. Segment Table

Frequency Table

CP Beam Table

CP Queue Table

Power Table

Beam Table

FES Status Tables

FES Table

CUP Table

Call Process Event Timers

Control Group Operational Parameters Table

Hash Tables

MT Database Hash Tables (RTIN, MIN and DN)

Virtual Network DE Hash Table

Routing List DB Hash Tables

Circuit Pool DB Hash Table

Net DB Hash Table

FES Status DB Hash Table

Virtual Network Counters Table

TDM Change Requests Table

Circuit Pool Status Counters Table

Circuit Pool Counters Table

Circuit Pool Queue Table

Spacecraft Power Table

MTs-on-Beam Table

MTs-commissioned Table

MT-SR Message Retries Table

MT-SR Congestion Events Table

GC-S Message Retries Table

IS Signaling Channel Stats Table

Call Record/Activity Tables

Call ID Activity Table

RTIN Activity Table

MTS Call Record

MT Management Call Records

In the preferred system configuration, the Group Controller resides onone VAX ft 810 and executes in multiple concurrent asynchronous VMSprocesses which timeshare the CPU. The functionality of each GC processis as herein described.

The GC is made up of the VMS processes listed below. There are twoProcess Groups: the GC Controller (GCC) group, and Control GroupManagement (CGM) group. The GCC and CGM Process Groups are describedbelow.

    ______________________________________                                        Process Name Priority    Process Group                                        ______________________________________                                        Configuration                                                                              Non-real-time                                                                             Control Group Mgmt                                   Process                                                                       Call Process Real-time   Control Group Mgmt                                   Monitor      Near        Control Group Mgmt                                   Process      real-time                                                        Check Field  Real-time   GC Controller                                        Generator                                                                     Process                                                                       ASK Configura-                                                                             Non-real-time                                                                             GC Controller                                        tion Manager                                                                  Process                                                                       Router       Real-time   GC Controller                                        Process                                                                       Router Con-  Non-real-time                                                                             GC Controller                                        figuration                                                                    ______________________________________                                    

Highest priority is given to the real-time processes for call handling.Second priority is given to near-real-time processes, which support callhandling by forwarding call records and supplying call traffic andperformance data to the NOC. Third priority is given to thenon-real-time processes which support ASK and Control Groupreconfiguration at the GC.

The GC processes are event-driven; between events, a process waits forinput on a queue. To reduce system load, waits are non-CPU-intensive.The highest priority processes are driven by call events; the lowestpriority processes are driven by NOC requests, Call Process requests,and internal timers set to configurable monitoring intervals. Inaddition to input from its queue, a process may use memory tables ordisk files, as shown on the Process Diagrams, for data required toprocess an event.

The GC architecture accommodates a move to multiple processors. The GCis divided into GC Controller (GCC) processes, and Control Group Manager(CGM) processes. In a distributed environment, there would be one GCController, consisting of the GC Router and both ASK Manager processes,supporting one to 16 Control Group Managers. CGMs function independentlyand can be distributed on multiple processors. A CGM can manage 1 to 16Control Groups, so there can be one CGM for all Control Groups (thecurrent configuration) or up to 16 distributed CGMs (one CGYM for eachControl Group). All processes for a CGM must be co-resident. The GCC canshare a processor with one or more CGMs, or can reside on a separateprocessor. The ASK Manager is stand-alone, and can be hosted on aseparate processor in any GC configuration.

GC Subsystems illustrated in FIG. 16 comprise the component subsystemsin the Group Controller and indicate where call processing and networkmanagement interfaces occur.

Configuration Process

The Configuration (Config) Process has multiple configuration controltasks. The Config Process controls the GC processing of Control Groupreconfigurations. It receives database transactions from the NOC via theDEC COTS product Reliable Transaction Router (RTR), prepares the update,loads the new data into memory, and coordinates with the Call Process tocomplete the update. The processing and synchronization of the Configand Call processes during a configuration change is designed to minimizeinterference with active calls. ASK reconfigurations are handled by theASK Configuration Manager.

The Config Process performs dual RTR roles. It performs as a server inNOC-initiated updates (#1, above) and a requester (client role) inGC-initiated database updates. As an RTR requester, the GC initiates RTRtransactions to distribute changes that originated in the GC CallProcess. One example of a GC initiated update is the change of a MTstate following commissioning; another is the GC's initiation of abulletin board update for congestion control.

Config receives AMS(R)S circuit requests, sends circuit blockingcommands to the Call Process, and returns the requested circuits to theNOC when they become available.

The Config Process has one RTR queue for reconfiguration messages fromthe NOC, including AMS(R)S requests. It also has a VMS mailbox for theCGS Software Backplane Process Control interface, and a mailbox forinternal timer notification.

Call Process

The Call Process is the heart of the real-time GC processing. Itincorporates the Finite State Machines (FSMs) for Call Processing, MTManagement, AMS(R)S Provisioning, and PVT/Commissioning. It alsocontains resource database access routines, error handlers, timers andutility functions that support the FSMs.

The input queues are prioritized as indicated on the GC CGMInter-process Communications Diagram. Incoming messages from each queueare processed in order. When an FSM message/event is processed, the CallProcess maps the message or event to its state data, performs the statetransition processing, and establishes the next state. Errors occurringin a state transition are handled by error routines associated with thecurrent state in the FSM. State data is maintained in the Active CallRecord Table, which allows shared read-access for use by supportfunctions in the Monitor process

The Call Process has one input queue established via the CGS Backplanefor signaling units, and Access security Check Fields (generated by theASK Manager). It also has VMS mailboxes for the CGS Software BackplaneProcess Control interface, internal time notification, internal messages(such as Circuits Available), AMS(R)S requests, and control groupreconfiguration requests from the Configuration Process.

Monitor Process

The Monitor Process provides the following Call Process supportfunctions:

1. Forward Call Records to the NOC

2. Buffer Call Records on disk

3. Save the MT Access Event History on disk

4. Generate call traffic statistics

5. Respond to Call Search Requests

6. Respond to Call Record Leftover Requests

Items 1-3 above are performed when a Call record is terminated. Themonitor process receives the Call Record from the Call Process, in aCall Termination message. This process forwards the final Call Recorddata to the NOC, increments counters for call statistics, stores theCall Record on disk for backup in case the NOC goes down, and stores theMT Access Event History on disk. the MT Access Event History buffersthat last ten accesses by MT by storing the time stamp of the end of thecall, termination reason, and access type (such as MT Management, Call,NR, etc.).

Statistics (Item 4) are generated by the Statistics Manager and polledby the Site Manager (DECmcc Agent) at configurable time intervals. Thesedata are derived from the Call Process (via the terminated CallRecords), and stored in shared memory tables for the Site Manager(DECmcc Agent).

Call Search requests (Item 5) are sent by the NOC to request the currentCall Record (if one exists) of a specific MT, and its Access EventHistory. The Monitor has read-access to the Active Call Record Tablemaintained by the Call Process for retrieving the call ID and callrecord, if it exists, for a MT.

Call Record Leftover requests (Item 6) are sent by the NOC when they areback online after some period of down- time. The request contains the IDof the last Call Record received by the NOC. The Monitor Processretrieves later records which it buffered on disk while the NOC wasdown.

The Monitor process has one input queue, established via the CGSBackplane, to receive Call Record Requests and Call Search Requestsrequests from the NOC. It has a VMS mailbox to receive terminated callrecords from the Call Process, a mailbox for the CGS Software BackplaneProcess Control interface, and a mailbox for internal timernotification.

GC Router Process

This process routes Call Process messages which do not have a ControlGroup ID. The GC Message Router Process has one input queue establishedvia the CGS Backplane to receive incoming SUs for internal routing. Italso has a VMS mailbox for the CGS Software Backplane Process Controlinterface, and a mailbox to receive reconfiguration messages from the GCRouter Configuration Process.

GC Router Configuration Process

This process is an RTR server process to accept reconfigurationtransactions from the NOC. This server is only notified of updates whenthe change affects the Control Group ID of a MT/MIN, IVDM. It cooperateswith the router process in the same manner that the Config Processcooperates with the Call Process to complete a transaction.

Router

This Process has an RTR input queue. It also has a VMS mailbox for theCGS Software Backplane Process Control interface.

ASK Configuration Manager Process

The ASK Configuration Manager Process configures the ASK database, basedon NOC inputs. The ASK Config Process has one RTR input queue. It alsohas a VMS mailbox for the CGS Software Backplane Process Controlinterface.

Check Field Generator Process

The Check Field Generator generates MT Check Fields in response to CallProcess requests. It also receives ASK reconfigurations from the ASKConfig Process, which it stores in the memory-resident ASK database.This process has one input queue established via the CGS Backplane toreceive check field requests from the Call Manager. This interface isvia the Message Layer because the ASK Manager may not be co-residentwith the Call Process it serves. It also has a VMS mailbox for the CGSSoftware Backplane Process Control interface, and a mailbox to receiveconfiguration messages from the ASK Config Process.

GC Queues Inter-Process Communications Sequence

Example: MT-PSTN Call

1. When a MT Access Request is received on the real-time CALL eventqueue, the CALL process sets up the call record, establishes a MTActivity Table entry for the call and determines whether the dialeddigits in the Access Request SU are complete.

2. If additional digits are required, the CALL process sends out arequest to the MT (see following Note 1 and the following referencednotes) and sets a timer for the expected response.

3. When the additional digits are received, the CALL process cancels theAdditional Digits Request timer. 4. The CALL process validates the MT,performs address screening, service permission checks, and routing. Ifall checks succeed, it allocates circuits and updates the OFFLINE GCCALL UPDATES process.

5. The CALL process requests the Access Security Check Field from theCHECK FIELD process. It sets a timer for the expected response. When theCheck Field is received, the CALL process cancels the timer for therequest.

6. The CALL process sends out Channel Assignments to the MT and FES. Itsets a timer and waits for the Setup Complete message.

7. When the Setup Complete is received from the SLSS, the CALL processcancels the Setup timer, updates the OFFLINE GC CALL UPDATES process,and sets a timer for the Call Status Monitoring interval.

8. When the Call Status Monitoring timer expires, the timer in the CALLProcess notifies the Call Manager which sends out a Call Status Requestand sets a timer for the response. When the Call Status Reply isreceived, the CALL process resets the monitoring interval timer.

9. When the Channel Release is received, the CALL process cancels theMonitor timer and closes out the call by releasing resources, clearingthe activity table, and sending a call termination event to the MONITORprocess.

10. The MONITOR process closes out the call record, updates the OFFLINEGC CALL UP-DATES process, performs any Statistics generation required,sends the call record to the NOC, and Buffers the call record to disk.

Note 1: All messages to/from the MT are sent via the NAP-S.

Note 2: If the response has not been received before the timer expired,the timer in the CALL process would have notified the Call Manager,which would have performed appropriate error handling.

Note 3: The CALL process can process other calls while it awaits for aresponse from another process on any given call.

GC Oueued Inter-Process Communications Example

Incremental Reconfiguration

1. When a distributed database transaction from the NOC is received onthe GC's RTR queue, the CONFIG process reads the transaction andprepares an update to the Local GC Configuration database. When thepreparation and validation are complete, the CONFIG process waits for avote request from the NOC. The CALL process cannot access the new datauntil the distributed transaction is complete.

2. When the CONFIG receives a vote request via RTR, it returns the GCvote. The GC will return VOTE/COMMIT if its local database validationand update preparation were successful, or VOTE/ABORT if an erroroccurred while processing the update. After casting the GC vote, theCONFIG process waits for a return code from RTR, indicating the finalstatus of the transaction. Final status is determined by RTR from thevotes cast by all participants.

3. If the final status of the transaction is COMMIT, then CONFIG sends amessage to CALL informing it of the reconfiguration. CALL updates itslinks to the reconfigured data and acknowledges the completion of theupdate. CALL can now access the data.

4. When the update is complete, the CONFIG process sends aReconfiguration Event to the NOC via the DECmcc AGENT process.

Both the Online and Offline GC's participate in a Control Groupreconfiguration since the Offline GC serves as another RTR partner ineach distributed Control Group transaction. The processing is the samecases.

NCC On/Off Line Switchover Process

As noted earlier, the fully expanded CGS system includes a second NCC oralternate NCC. This separate physical copy of the NCC maintains nearreal-time communication with the active on-line NOC and the activeon-line NCC via the MSS Internetwork using the TCP/IP protocol. The MSSInternetwork communication path allows the alternate NCC to begeographically separated from the on-line NOC and the on-line NCC. Thenear real time communication allows the off-line NCC to maintain a "hot"standby status such that it could become the active on-line NCC with aminimum amount of elapsed time and "lost processing" once the switchbetween NCCs is initiated.

In order to maintain an up-to-date status at the off-line NCC, theapplicable database updates at the on-line NOC will be issued as RTRtransactions to maintain lock-step database concurrence across the twoNCCs. The categories of message sent to the off-line NCC include:

MT Customer Configuration

Virtual Network and Routing Configurations

FES Configuration

Channel Unit Pool Configuration

Satellite Resource Configuration

Control Group Operation Parameters

Bulletin Board Data

To maintain lock step with ongoing real time call processing, theoff-line NCC receives call processing information from the on-line NCCon a call-by-call basis.

The major categories of information moving from the off-line NCC to theon-line include the following:

Call records with frequencies allocated to a call setup

Call records for a call after setup is complete

Call record for a call after the frequencies have been released.

The off-line NCC uses this information to maintain call records andfrequency allocations dynamically such that the off-line NCC canimmediately assume control of the in-process active call suite and iscompletely aware of the current in-use frequencies to continue with newcall setups and "old" call releases.

The on-line to off-line NCC switch over may occur as scheduled activity(e.g., periodic maintenance, major NCC H/W or S/W configuration upgrade,etc.) or as a result of a failure of the current on-line NCC.

The scheduled switch over process is the following:

The on-line NOC or local NCC operator alerts the on-line NCC to initiateprocessing phase out and suspend active communication with itsassociated CGS internal element.

The on-line NCC alerts the off-line NCC that all processing has beensuspended and all elements associated with the NCC are waiting for acommunication restart.

The off-line NCC commands the on-line NCC to go to passive standby underits own local operator control. At this point the previous off-line NCCis now the new active on-line NCC.

The new on-line NCC begins a communication restart sequence with itsassociated CGS elements.

This completes the scheduled switch over from an active on-line NCC tothe off-line NCC.

The fail over process is initiated by the on-line NOC. The process flowis the following:

The on-line NOC commands the on-line NCC to go to passive standby underlocal operator control. This is an insurance command to attempt toeliminate the failed NCC from active participation in CGS processing.

The on-line NOC commands the off-line NCC to go active.

The on-line NOC commands all NCC associated elements to suspendcommunication with the old on-line NCC and wait for an NCCcommunications restart command.

The on-line NOC commands the new on-line NCC to begin a communicationsrestart with all of its associated elements.

The new on-line NCC begins a communications restart sequence with all ofits associated elements.

This completes the fail over sequence. If the original active on-lineNCC is not capable of fulfilling its role in the fail over sequence, theswitch over will be accomplished via NOC operator to NCC operatorcommunication to suspend the operations of the original on-line NCC andthen via NOC MMI to command the on-line NOC MMI to command the on-lineNOC to pick up the remainder of the failover sequence.

The Gateway Switch (GWS) is the communications hub for Feederlink EarthStations (FESs) to provide call processing services to MT users andhandles cellular Intersystem Handoff (IHO), Automatic Roaming (AR) andCall Delivery (CD).

The GWS provides the following interfaces:

Public Switched Telephone Network (PSTN)

Private Network (PN)

Cellular Terrestrial Network (CTN)

Network Operations Center (NOC)

Station Logic and Signaling Subsystem (SLSS)

Network Applications Processor (NAP)

The GWS acts as a gateway between the users of the satellite system andthe Public Switched Telephone Network (PSTN), Private Networks (PN), andCellular Terrestrial Network (CTN). Within the FES, the GWS connectsthrough Communication Channel Units (CCU) and the satellite system forbearer channel connections to Mobile Terminals.

The GWS also connects through a Station Logic and Signaling Subsystem(SLSS) for a control path to and from the Network Control Center (NCC).The GWS views the MSS call processing resources as cell site(s). Thecell site emulation performed by the GC, SLSS, NAPs, and CUs allows thesatellite system to be configured into the DMS-MTX as an analog cellsite.

With respect to the MSS, the basic functions of the GWS are:

manage the PSTN/PN interfaces

manage CTN interfaces

receive and process connections and feature control messages from theSLSS processes

provide various operational and administrative support for the switchingoperations of the network

provide various Call Service Features to the MT user

The basic role of the GWS within the Mobile Satellite Services (MSS)system is shown in FIG. 17. As indicated, the GWS acts as a gatewaybetween the users of the satellite system and the Public SwitchedTelephone Network (PSTN) or Private Networks (PNs). Within the FES, theGWS connects through Communication Channel Units (CCUs) and thesatellite system for bearer channel connections to Mobile EarthTerminals (METs). The GWS also connects through a Station Logic andSignaling Subsystem (SLSS) for a control path to and from the NetworkControl Center (NCC).

In contrast to the hardware interfaces shown in FIG. 17, FIG. 18 depictsthe basic call processing interaction between the GWS and other elementswithin and outside of the overall MSS system. As indicated, standardCall Processing (CP) software within the GWS interfaces with a CallControl Element (CCE) process in the SLSS and with a Group Controller(GC) processing the NCC.

With respect to the MSS, the basic functions of CP in the GWS are: tomanage the PSTN/PN interfaces, receive and process connection andfeature control messages from the CCE and GC processes, and providevarious operational and administrative support for the switchingoperations of the network.

In addition to the internal interfaces of the MSS, the GWS CP alsointerfaces CP control elements of the PSTN or the PNs. In the most basicapplications the various CP processes only exchange addressing (dialing)information for call routing. In more advanced applications involvingSS7 or ISDN networks, the CPs exchange information for advanced featuressuch as calling number identification, terminal characteristics, callingrestrictions, subaddressing, routing requirements, etc.

Note that since the GWS is expected to be a variant of a public networkswitching system, there will be functional similarities between the GWSCP and the PSTN CP and PN CP.

The GWS physically resides as part of the Feederlink Earth Station (FES)(see FIG. 17). The FES is the network interface point for theinterconnection of satellite resources and terrestrial resources. TheGWS can best be envisioned as an end-office, connecting to Mobile EarthTerminals (METs) in lieu of subscriber telephones. The METs are specialpurpose terminal sets communicating, via satellite, to the FeederlinkEarth Station.

The METs, in conjunction with other functionality of the FES, canprovide circuit switched voice, data and facsimile services. A highlycompressed method of voice encoding is used over the satellite channel.Likewise, the satellite channel can accommodate 4800 bps digital datawhich is converted to voiceband modulated data (in a Hayes compatiblemodem format) in the CCU which interfaces to the GWS. In addition, thesystem supports facsimile traffic complying with the Group 3 standard.Not withstanding the above, services appear at the GWS via 64-kbps(DS-0) bearer channels contained within T-1 physical links. Signallingrelated to MET originated calls is handled via separate signaling linksfrom the SLSS as described subsequently.

The GWS supports the MSS network provision of Mobile Telephony Service(MTS). MTS is defined as voice, circuit switched data, and Group 3 FAX.At the highest functional level, the following telephony functions shallbe supported in the MSS.

Establish, maintain and disconnect Mobile Earth Terminal (MET) circuitswitched connections.

The generation and reporting of Automatic Message Accounting (AMA)events to be used for subscriber billing and operations purposes.

Support of Operations, Administration and Maintenance (OA&M) functionsand interface to external support systems.

Support and interface to voice messaging systems for the networkprovision of value-added features.

Circuit switched connections may be any one of the following:

MET to MET

MET to/from PSTN (IEC or LEC)

MET to/from Private Network

MET to Alternate Operator Services

MET/PSTN/PN to Voice Messaging System

AMA records of call events shall be maintained and reported by the GWS.The basis for this functionality is LSSGR AMA compliant with some uniqueMSS data collection required.

The functionality of the Gateway Switching Subsystem has been specified,to the extent possible, to be a generic PSTN, digital switching system.It is desirable to minimize the non-recurring engineering effort imposedon potential switch vendors. Toward this objective, the functionalrequirements are functionally similar to Bellcore's LATA SwitchingSystem, Generic Requirements (LSSGR) document, incorporated herein byreference.

The one area recognized as requiring customized engineering is theinterface to the satellite resources, as described below.

The GWS interfaces are grouped into four categories: the TelephoneNetwork Interfaces, Mobile Access Interfaces, the Operations SupportInterfaces and the Ancillary Equipment Interfaces. CommunicationsChannel Unit connections are bearer circuits (64-kbps DS-0) carryingvoice, circuit switched data or facsimile. The connections to theStation Logic and Signaling Subsystem and the Network Control Center aresignalling interfaces.

Operations, maintenance and administration interfaces are to the NetworkOperations Center. Ancillary interfaces, for example, to Voice Messagingsystems are also provided. Telephony network interfaces are shown to theleft side of the GWS. PSTN interfaces will be to both the Local ExchangeCarrier (LEC) and one or more Inter-Exchange Carriers (IEC). MultiplePrivate Networks must also be accommodated.

Alternate Operator Services (AOS) provided by other companies may beused initially for the support of Calling Card/Credit Card billing andoperator assisted calling. This function may also be accommodated usingso-called "robot operators" which are a specialized version of anInteractive Voice Response (IVR) system.

Trunk access to the PSTN is required. Physical access shall be via T-1facilities. Extended Superframe format T-1s with ANSI recommended alarmsand performance reporting is highly recommended. PSTN access shallsupport in-band, multi-frequency signaling to and from one or more IECsand the LEC.

Trunk access is also required to Private Networks. Again, physicalaccess shall be via T-1 facilities with analog interfaces, if required,being accommodated with channel banks outside the scope of thisspecification. Again, ESF format T-1s are recommended.

Alternate Operator Services may be used in the network for the provisionof operator assisted calls and credit card billing validation. Physicalaccess to the AOS service provider shall be via T-1 facilities.Collectively, the resources required to support satellite communicationsare referred to as the Satellite Resources. These resources include theCommunications Channel Units, Signaling Channel Units, the Station Logicand Signaling Subsystem and the Network Control Center. Functionally, aGSM `A` interface is recommended because it best accommodates thefundamental requirements of the satellite interface.

The GSM Recommendation `A` interface provides the two fundamentalcharacteristics necessary to support the MTS requirements; 64-kbpsbearer channels and out-of-band signaling channels. Out-of-bandsignalling is required to support the interactive nature of callprocessing between the GWS and the NCC. The NCC has responsibility forthree primary functions, as related to the Gateway Switching Subsystemand call processing functionality.

Management and allocation of the Satellite Resources

Interworking with Cellular networks for Mobility Management

Real-time management and administration of the subscriber database

Because of this parsing of functionality, the GWS must interwork withthe NCC (via the SLSS) on all call attempts. As originating attempts arepresented at the Communications Channel Units, signalling and subscriberinformation, necessary for the handling of the call attempt, will becommunicated across the SLSS signaling interface.

Likewise, terminating attempts from the PSTN or private networks, to aMET subscriber cannot be handled until the GWS and NCC have communicatedto identify the satellite resources to be used, and anysubscriber-related data necessary in processing the call.

The Communications Channel Unit interface shall be via DS1 cross connectfacilities. Each DS1 cross connect signal provides 24, 64-kbps (DS-0)PCM channels. Communications Channel Units have no fixed associationwith MET terminals or subscribers. This association is supplied to theGWS on a per call basis by the NCC.

Note: A DS1 cross connect signal is functionally equivalent to a T-1signal that is used for equipment interconnections between equipments ina building.

Because of the integral role that GWS/NCC communications (via the SLSS)plays in call processing, the SLSS interface must be redundant, betraffic dimensionable, provide for reliable communication of messages,provide reliable communication subsystem recovery in the event ofhardware or software failures, and support the OSI model for opensystems interconnection. Signalling System 7 (SS7) is recommended as themost robust signaling protocol available to satisfy these requirements.

The primary function of the Network Operations Center (NOC) is the nonreal time management and control of MSS resources. The GWS is requiredto interface with the NOC for the following functions.

System surveillance and monitoring

Error logging and tracking

Control of diagnostic testing and result analysis

Management of network restoration procedures

Accumulation of AMA call events

Database management and administration

Accumulation and reporting of network performance statistics

Accumulation and reporting of network configuration data

Security Management

The Gateway Switching Subsystem shall interface to the NOC for itsinternal Memory Administration, AMA Teleprocessing, Network Management,Measurements and Statistic reporting and System Status Monitoring andSurveillance.

The NOC interface(s) shall meet OSI requirements for Open SystemsInterconnection, such as X.25. The interface(s) shall support multiplephysical or logical channels for each function. If multiple logicalchannels are provided on a single physical interface, each logicalsegment of the interface shall be dimensionable based on the datathrough-put demands placed on it.

The Traffic Data Collection System is referenced as the interface forthe communication of traffic measurements and statistics to the NOC.This interface is specified in LSSGR FSD 45-09-0100. The GWS interfaceswith the NOC to provide remote memory administration functionality. TheMemory Administration Interface shall be provided per the requirementsstated in LSSGR FSD 45-01-0701.

The GWS AMA Teleprocessing Interface is provided in the form of an AMATransmitter (AMAT), permitting the store, poll and forward transmittalof GWS collected AMA records to the NOC. This interface meets genericrequirements of an AMAT. Network management messaging is defined inBellcore LSSGR, FSD 45-18-0403 and FSD 45-09-0100.

Remote Switching Maintenance Interfaces is provided in eithersynchronous or asynchronous form. Bellcore LSSGR FSD 35-08-0100 and FSD35-08-0200 provide details of those interfaces. The synchronousinterface is preferred. This interface supports a Voice Messaging Systemwith the capability of delivering original called number identificationfor forwarded numbers so the voice messaging system can providepersonalized greetings.

The Gateway Switch consists of multiple items illustrated in FIG. 19.The DMS-MTX SNSE is the main component of the GWS. This componentprovides the control to perform call management and system controlfunctions. The SNSE was chosen for the optimal cost and size. Thisconfiguration supports a 16K port switch. The delivered hardware isMotorola 68020/20 MHz based. The SNSE consists of the followingsub-components:

Message Switch (MS)--This component is commonly referred to as theDMS-BUS. The DMS-bus is the messaging hub of the system. The messageswitch is a fully duplicated entity that provides message routingbetween system components. A 32 bit MC68020 microprocessor, supported by6 megabytes of memory, manages the overall performance of the DMS-bus.

Enhanced Network (ENET). The third shelf of the SCC cabinet contains theENET. The ENET is a conventional matrix timeswitch designed to achievehigh density at low power consumption. The ENET provides a duplicated,junctorless, nonblocking network. The ENET Cross-points are optimizedfor a 16K channel network.

Computing Module (CM)--The bottom shelf of the SCC cabinet contains theCM. The CM is fully duplicated, synchronized, computing module. The CMutilizes the 32 bit Motorola MC68020 microprocessor. There are 216megabytes of call and program store capacity (maximum growth) in eachCM.

System Load Module (SLM)--The bottom shelf of the SCC also contains theSLM. The SLM provides for rapid loading of office images and updates. Itconsists of a 600 megabyte hard disk and a 150 megabyte high-speedstreaming tape drive to permit fast memory loading. There are two SLMs.Each is directly connected to its corresponding CM.

The Intelligent Cellular Peripheral (ICP) is a dual shelf (ICP 0 andICP 1) peripheral designed to provide the necessary functions forsupporting a call processing interface for cell site communications. Thedual shelves operate in hot standby mode. That is, one shelf is active,providing the necessary processing and control functions, while theadjacent shelf is in hot standby mode, able to take over if a faultoccurs on the active shelf. The call processing interface handles allsignaling between the DMS-MTX and the NAP/SLSS to support incoming andoutgoing calls, and intersystem handoff. The ICP interface to theNAP/SLSS is done via cell site emulation. The satellite resources (GC,SLSS, NAP, CU) emulate cell site(s) for the ICP. Each "cell site"communicates to the ICP via LAPD communications on a DS0 of the T1connecting the satellite resources to the GWS. The ICP views thesatellite resources as multiple analog cell sites.

The communicating to and from a cell site is done using a Layer 3proprietary Northern Telecom cell site protocol. In addition toproviding the necessary mechanism to allow the MSS to interconnect tothe GWS and provide call processing services, the emulation of a cellsite presents some situations that are applicable to cellulartelecommunications, but do not have any meaning to satellitetelecommunications. These situations are handled by the SLSS and NAP ina manner to satisfy the ICP protocol.

The following list outlines the hardware support that an ICP providesfor connecting to the MSS.

10 T1s per ICP

240 DS0 Channels

2 DS0s per Cell Site used for LAP-D Communication (1 Active, 1 Standby)

118 DS0 Voice Connections per Cell Site (Maximum)

The ICP connects to the DMS-MTX via one DS 512 fiber link. The DMS-MTXcan accommodate seven ICPs providing 1512 channels between the GWS andthe NAP/SLSS.

The Digital Trunk Controller (DTC) is a dual shelf (DTC 0 and DTC 1)peripheral designed to provide the necessary functions for supportingtrunk terminations to the outside networks. The dual shelves operate inhot standby mode. That is, one shelf is active, providing the necessaryprocessing and control functions, while the adjacent shelf is in hotstandby mode, able to take over if a fault occurs on the active shelf.The DMS-MTX will accommodate thirteen DTCs to provide for 255 T-1connections. (150 CTN, 105 PSTN/PN--max configuration).

The DTC provides the following:

T1 trunks to process incoming and outgoing call processing (DID and DOTtrunks)

T1 trunks to provide an interface to private network PBXs.

T1 trunks to Voice Mail systems (Option)

T1 trunks for Intersystem Handoff voice connections to the CTN (AMSC)

T1 trunks to PBX to provide support for administration

T1 trunks to a Channel Bank for four wire E&M connections

The DTC connects to the DMS-MTX via one DS512 fiber link. The DTC cansupport up to twenty T1s. This provides 480 channels per DTC.

The Link Peripheral Processor (LPP) in the DMS-MTX provides an interfaceto Northern SS7 networks to provide the following:

CTN SS7 network to provide point to point IS-41 interface over an F-linkto another SS7 CTN node.

CTN SS7 network to provide IS-41 messaging interface to an STP over astandard A-link.

The LPP connects to the DMS-MTX via sixteen DS30 links. The Input/OutputController (IOC) provides the interfaces for the microprocessor basedInput/Output Device (IOD) controllers. The IOC relays messages to IODcontrollers.

The IOC in the DMS-MTX provides the interface for the following devices:

Maintenance and Administration Positions (MAP)--The MAP is used foroverall maintenance and administration of the DMS office. The MAP is astandard VT100 format that provides access to switch table sandconfiguration.

Printers--The printers connected to the IOC are utilized to dump logreports and operational measurements to paper.

Disk Drive Units (DDU)--The DDU consists of a disk drive and powerconverter card. The purpose of the DDU is to provide storage for CDRs,log files, and other switch output files.

Magnetic Tape Drive (MTD)--The MTD is a 9-track tape unit used to storedata for applications. These applications include OMs, troublediagnostic data, CDRs, customer data modification, and office datamodification.

Device Independent Recording Package (DIRP)--This is part of the IODsubsystems and operates under the control of the IOC. The main purposeof DIRP is to redirect output from switch processes to output devicessuch as printers and disk drives. DIRP controls the data flow fromoriginating subsystems such as CDR, OM, of JF, and the recording deviceson which the data is to be stored.

X.25 layer 2 and Layer 3 IS-41 to the CTN--The X.25 connections providedt the CTN provide the carriage of IS41 signaling to and from otherMobile Switching Centers (MSC)s. This connection can operate at 9.6kbps, 19.2 kbps, or 56 kbps depending on the card and type of X.25connection/modem.

Call Detail Record (CDR) Interface--The CDR interface provides themechanism for the transfer of billing records from the switch to aperipheral device at near real time. For the MSS this peripheral deviceis the Network Operations Center (NOC).

Dial up Connection Interface--The Dialup Connection allows the transferof switch data over a telephone line. These interfaces are commonly usedas remote MAPs.

Operations and Maintenance Connections--The O&M interface is provided bya connection through the IOC to an external device for the transfer ofLogs and OMs from the switch to a device for processing.

The DMS-MTX contains additional devices used for trunking. The MCAMcabinet type contains the following DMS-MTX devices:

Package Trunk Module (PTM)--The PTM is a system peripheral module thatencodes and multiplexes incoming speech from a maximum of 30 analogtrunks into 8-bit pulse code modulation format. The PTM combinesinformation with internal and supervisory control signals fortransmission at 2.56 mbs to the network.

Service Trunk Module (STM)--The STM is a reduced size Maintenance TrunkModule (MTM). The MTM primary function is to interface service, test,and maintenance circuits. Each STM operates independent of the other andfunctions as a separate peripheral module. The STM accepts analogtrunks, digital service circuits, or both, and processes the signals toa common PCM format. One type of STM is the Digital RecordedAnnouncement Machine (DRAM). The DRAM provides recorded announcementsthat have been stored in digital format. The DRAM can provide fullydigitized voice announcements for up to thirty separate channelssimultaneously. A fully configured DRAM can provide up to sixty-fourseparate announcements.

Power Distribution panel (PDP)--The PDP performs the power sourcedistribution for the DMS-MTX.

The DE-4E Smart Terminal is the chosen Channel Bank for CGS. This SmartTerminal is an intelligent microprocessor based EMI compliant systemdesigned to provide point to point private lines. The single-digroupDE-4E Smart Channel Bank is capable of housing up to 24 "serviceadaptive" channel units. The channel units are available for two wire orfour wire circuits and various signaling including E&M type 1, 2 and 3.

The Timing Signal Generator (TSG) is used to derive system clocking forSS7 signaling. The TSG derives its timing from T-1s connected to a tolloffice with a stratum three or higher clock. The TSG then distributestiming to the various components. Note that the TSG is only used whenSS7 signaling is required. The DCD-400 from Telecom Solutions is thechosen model for the GWS TSG.

When the TSG is not used to provide system clocking, a standard clockcard in the SNSE cabinet is used to distribute clocking to the DMS-MTX.

To provide the ability to patch T-1s from the DTC and ICP to variousother pieces of hardware, Channel Banks, MUXs, and MAPs for example, theMTX is equipped with two Digital Signal Crossconnection Patch Panel(DSX) patch panels, such as the DSX-29/56 model manufactured by ACDTelecommunications. The patch panel provides the following:

56 connections total

Wire-wrap rear cross-connects

Horizontal and vertical rings

Flush 3" or 4" mountings

Jacks numbered A 1-28, B 1-28

Red flashing LEDs

Bantam jack monitoring and patching

The Main Distribution Frame (MDF) is the demarcation point for four wireE&M trunks.

The GWS software and hardware will provide for the following VoiceService Features in addition to the basic call processing.

Call Forwarding Unconditional--The GWS will control the forwarding ofcalls made to MT users that have activated this call forwarding feature.When this feature is activated, calls are forwarded to the CFU numberwithout attempting to contact the MT user.

Call Forwarding Busy--The GWS will control the forwarding of calls madeto MT users that have activated this call forwarding feature. When thisfeature is activated, incoming calls to a MT are forwarded if the MT isinvolved in another call. Note that the incoming call must be to thesame MIN that the MT is currently using.

Call Forwarding No Reply--The GWS will control the forwarding of callsmade to MT users that have activated this call forwarding feature. Whenthis feature is activated, incoming calls to a MT are forwarded if theMT either does not respond to the page request, or times out ringing.

Call Waiting--The GWS will control this feature. If a MT user isinvolved in a call and receives another call to that MIN and has CallWaiting, the DMS-MTX puts the incoming call on hold and applies a 440 Hztone to the voiceband to notify the MT of the other call. If the MT userdecides to toggle to the other call, the DMS-MTX connects the secondcall to the MT and puts the original call on hold.

Conference Calling--The GWS will control this feature. If a MT userdecides to add a third party to a call (the DMS-MTX supports a maximumof three parties in a call), the MTX puts the first call on hold,allocates a conference port and routes the second call. Once the MT usersignals the MTX to conference the calls, the MTX connects all threeparties together. If the MT who originated the first call was theoriginator of the conference, and he hands up, all parties aredisconnected.

Call Transfer--The GWS will control this feature. If a MT was called byanother party and wishes to transfer the call, the MTX puts the firstcall on hold and allocates a conference port and routes the second call.At this point there are three options for the MT.

Option 1--Hang up before the party answers. In this case the MTX willtransfer the call.

Option 2--Wait for the other party to answer, talk and hang up withoutever conferencing in the other party from the first call. At this time,the MTX will transfer the call.

Option 3--Wait for the other party to answer, conference in the otherparty. After conversing in a conference, hang up. At this time, the MTXwill transfer the call.

Call Forwarding Congestion--The GWS will control this feature. If thesituation arises at the GWS where all of a particular trunk group isbusy to or from a switch, the DMS-MTX has the capability to datafill asecondary route that will be used if the primary route is busy or out ofservice. There are two other possible call forwarding scenarios that theswitch addresses. First, if there are no channel units available for aparticular call, the MTX will send the call to an announcement. Next, ifthere are channel units available, but no satellite frequencies, the MTXwill either send the call to the page timeout announcement, or reroutethe call if the MT user has this feature activated for the particularMIN being called.

Call Barring--The GWS will control part of this feature. The GWS willvalidate the MIN and ESN of a MT either via a lookup in the HLR or bycommunicating to the Home MSC of the MT via IS41. The GWS provides lineoptions in the HLR to allow restrictions such as denied originations(DOR), denied terminations (DTM), or suspended service (RSUS, SUS) to beplaced on MT users.

Operator Assistance--The GWS will control this feature. The DMS-MTXprovides the ability to route calls that request operator services to aroute that will send the call to an operator switch.

Alternate Account Code Charging--The GWS provides the ability for usersto append a digit code (Account Code) at the end of the dialed digitstring to differentiate calls made from different accounts. This stringis not validated by the MTX and is strictly for customer billingclarification.

The call detail record (CDR) system is used to record comprehensivebilling and other data on all calls. The CDR system accepts callinformation data from the DMS system. The data is then recorded on atape, disk, or sent to the NOC by using the standard Multi-NetworkProtocol (MNP) protocol manufactured by Northern Telecom used totransfer CDR billing data from a DMS-MTX switch to a remote billingprocessor at near real-time.

The CDR's are recorded on the hard disk at the GWS and sent to the NOCby the X.25 (MNP) using a V.35 interface. There is a redundant X.25 linkthat can be enabled in the event of a failure of the primary path to theNOC. Since the CDRs are written to the hard disk at the GWS, thetransfer on the backup link can begin at the point where the transferfailed in the case of a redundancy switch. This method insures thatCDR's are not lost in the event of a failure in the primary path fromthe GWS to the NOC. The CDR fields are described in Table A.

The message protocol used for MNP contains the following Protocol DataUnits (PDU):

ACS-SFO: Access Request Message-Start File Outgoing

This message contains the information necessary for the far end to beginestablishment of a file transfer. (35 octets)

STS-ACK: Status Message-Access Request Acknowledge

This message is sent in response to the ACS-SFO message when the NOCaccepts the billing file request. (3 octets)

CNT-PRT: Control Message-Set Device to Print Mode

This message is sent to the NOC when the GWS is ready to transfer data.(2 octets)

CNT-RED: Control Message-Set Device to Read Mode

This message is sent by the NOC to start the file transfer. (2 octets)

STS-EOB: Status Message-End of Block

This message contains the sequence number of the previous sent datablock. This message is sent by the GWS to describe the data block justsent. (8 octets)

CNT-RNB: Status Message-Request Next Block

This message contains the sequence number of the received data block.This indicates that the data blocks up to the sequence number weresuccessfully received by the NOC. (6 octets)

STS-EOF: Status Message-End of File

This message is sent by the GWS when the entire billing file istransferred. (2 octets)

STS-CPL: Status Message-Access Complete

This message is sent by both the GWS and the NOC to wrap up the currentsession. (2 octets)

DATA: Application Data

This message is a 2K octet block of data, and is followed by the STS-EOBmessage. It contains billing information which is retrieved from thebilling file on the disk.

The following describes the basic message flow between the GWS and theNOC for the transfer of CDRs via MNP.

Step 1: The GWS has a billing file ready to transfer. The SVC of X.25 atlayer 3 has been established between the GWS and the NOC.

Step 2: The protocol messages have been exchanged for startup, and bothends have recognized the billing file. At this point, the file transferis ready to start.

Step 3: The data blocks are sent from the GWS to the NOC. In theopposite direction, acknowledgement messages are sent back to the GWS tonotify it of successful transfer of a data block. This example, shows awindow size of one. This means that a CNT-RNB is expected before anotherdata block is sent from the GWS. For applications with larger windowsizes, i.e., greater than 1, the GWS will not wait for a NTR-RNB for adata block before transmitting the other data blocks contained in thewindow. The CNT-RNBs for each block are still expected, but can arriveback at the GWS in any order.

Step 4: When reaching the end of the billing file, the STS-EOF messageis sent to the NOC to notify it of the completion of the file transfer.Subsequently, the STS-CPL message is exchanged to end the session.

Step 5: The GWS shuts down the X.25 SVC link between the GWS and theNOC.

Some MSS system users have voice communication requirements that are notmet by MTS and Mobile Radio Service (MRS). They need to communicate in avirtual network arrangement that allows each member of the group to hearwhat any other user is saying. Each member of the group can also talkwhen needed. The system behaves like a radio multi-party line. Publicservices and law enforcement agencies are typical users of this service,which is normally provided by either traditional terrestrial radionetworks or by the more recent trunked radio systems. These trunkedsystems, generally in the 800-900 MHz band, provide groups of end userswith virtual private systems by assigning frequencies to CUGs on ademand basis. The virtual network service is meant to be the satelliteequivalent of terrestrial trunked systems ("trunking" for short), andcould be pictured as a "Satellite Trunked Radio Service", or "SatelliteTrunking".

The virtual network service provides the capability described in theprevious paragraph in a cost effective manner:

as one shared satellite demand period circuit per virtual network isutilized rather than one circuit per mobile user, the cost per minute ofa group conversation would be much less expensive to the owner of thegroup, and

as the call set-up time for one shared circuit per virtual networkcompared to an MRS multi-user conference set-up time is likely to bemore acceptable to a group end user/operator, who normally expects to beable to talk as soon as the handset/microphone is taken off-hook.

A virtual network is defined as a partition of METs and FESs within acontrol group having particular connectivity attributes. Each virtualnetwork has a defined set of service features to which its users maysubscribe as a whole or individually. As illustrated in FIG. 20, avirtual network is associated with a group of FESs and METs. It ispossible for an FES to belong to a particular virtual network or beshared by multiple virtual networks. It is also possible for a MET tobelong to a maximum of 16 different virtual networks. Interconnectionbetween different virtual networks is supported by the MSS system.

The database files on the METs and the communications nets of asubscribing organization comprise a Virtual Network (VN) within the MSSsystem, and is assigned a Virtual Network identification number. All ofthe METs in a VN may communicate with each other.

An overview of the MSS system with the VN service is illustrated in FIG.21. FIG. 21 illustrates the basic concept and elements involved inestablishment of communications and control in the virtual networksystem. METs access the system via one or more L-band beams. Each beamcontains one or more signaling channels for network control and callestablishment and a number of communications channels for provision ofvirtual network services to METs.

The L-band frequencies are translated to Ku-band frequencies by thesatellite 12. The Network Control Center 14 is responsible for the realtime allocation of channels to support virtual network calls. The baseFeederlink Earth Station 16 is responsible for re-transmission on theoutbound channel of the MET transmissions received on the inboundchannel, control of the virtual network call, and interfacing thevirtual network call to terrestrial private networks.

Virtual network service is available to users in the virtual networkgroup on subscription to MSS. A subscribing organization may comprise anumber of METs grouped by their communication needs. A virtual privatecommunication net is established for each of these groups or subgroups.

The base FES 16 can interconnect the virtual network call to terrestrialprivate networks so that a dispatcher located within the private networkcan participate in the conversation. A dispatch facility may be directlyconnected to the base FES 16, or may use leased PSTN or dial-up access,or may use a Mobile Radio Service (MRSA) circuit. An example of avirtual network service subscribing organization with severalcommunication virtual networks is depicted in FIG. 22.

The virtual network MET operates in a virtual network and receives voicetransmissions from all other MET users in the same virtual networkgroup, and the base FES. The MET supports virtual network service on asingle demand period circuit per beam, which is shared by the entiregroup. The MET requiring communications will be given the virtualnetwork (VN) ID for the net and since different VN groups may benecessary for different purposes, the MET may be given a number ofdifferent VN IDs.

VN IDs may represent organizational groups such as fleets or sub-fleets.VN IDs may represent functional groups such as a command unit whichdraws on mobile users from more than one fleet or sub-fleet. VN IDs mayrepresent geographic configurations such as an east or west area, orboth.

Virtual Network Configuration

Each GC receives from the NOC, via the NCC Controller, the VirtualNetwork configuration database from each customer network. The databaseis processed and organized to support and optimize all real-time callprocessing accesses for Virtual Network attributes and configurationdata. During operation the GC shall support the incremental addition to,deletion from, or modification to, the Virtual Network configurationdatabase, under direction of the NOC.

To support configuration changes each GC shall control the operatingstate of its Virtual Networks in accordance with NOC directives.Transitions between the following Virtual Network operational statesshall be supported:

a. Inactive/initialized. Ready to become active.

b. Active--normal. Processing traffic normally.

c. Active--unloading. Blocking new calls and servicing disconnects tounload traffic.

d. Active--unloaded. Blocking new calls; traffic has been unloaded.

The NCC Controller is able to display each GC Virtual Networkconfiguration and status tables locally via the NCCTE man-machineinterface, or to transmit Virtual Network configuration and statustables upon request to the NOC via the MSS Internetwork.

Virtual Network Call Status

These tables contain call status data for each Virtual Network:

a. Call data records:

i. Call Identifier

ii. FTIN

iii. RTIN

iv. MET supplied dial digits

v. Terrestrial network supplied dial digits

vi. MET port id

vii. Service type (voice, data, fax and expansion to new service types)

viii. Connection type (MET to terrestrial, MET to MET, terrestrial toMET.

ix. Control Group ID

x. Virtual Network

xi. Advanced features used

xii. FES Terminal

xiii. Circuit pool utilized.

xiv. L-band beam accessed.

xv. Forward link Ku-Band frequency used.

xvi. Forward link L-Band frequency used.

xvii. Return link L-Band frequency used.

xviii. Return link Ku-Band frequency used.

xix. Forward link power level authorization.

xx. Queueing flag.

xxi. Priority for queueing.

xxii. Date/time of access request.

xxiii. Date/time of channel assignment.

xxiv. Date/time of setup complete.

xxv. Date/time of channel release.

xxvi. Call clearing reason code.

b. Aggregate calls in progress.

c. Current call processing completion rat.e

d. Current call blocking rate.

Virtual Network Configuration Table

This table defines the configuration databases for each Virtual Network,served by the Control Group. The database provides a complete definitionof each Virtual Network's service permissions, routing rules, andaddress screening constraints. This table also contains the NOC assignedoperating state for each Virtual Network--Inactive/Initialized,Active-Normal, Active-Unloading, Active-Unloaded. The GC supportsforeground and background Virtual Network Configuration tables tofacilitate the network configuration change procedures.

Virtual Network Functional Characteristics

This section describes the virtual networking capabilities offered bythe MSS. Generally from a functional perspective, a virtual networkinvolves membership rules, a dialing plan, and a set of dialingallowances and/or restrictions.

Each MET is a member of at least one VN. A MET is optionally a member ofup to 15 additional VNs. One VN of which a MET is a member be denoted asthe default VN for that MET. MET VN membership(s) is provided on asubscription basis. Dual-mode METs (METs capable of both cellular andMSS operation) that are registered in the MSS shall constitute aspecific VN denoted VN-C. No other METs is members of VN-C.

VN MET addresses are selected from blocks of numbers allocated from theNorth American PSTN. Since MET numbers are selected from the NorthAmerican PSTN, and no number translation is performed, MET and PSTN/PNnumbers are disjoint. A MET user has the capability to select, on acall-by-call basis, the specific VN within which he/she wishes to act;this VN is denoted the "acting VN". The MET user indicates the acting VNby an optional suffix. If no suffix is presented, the acting VN is thedefault VN defined for the MET. The MET must be a member of any VNselected by the suffix.

Within an acting VN:

a. MET-to-MET calls utilize 7-digit (NXX-XXXX) dialing, or 10-digit(NPA-NXX-XXXX) dialing. Other dialing plans for MET-to-MET calling maybe offered as options.

b. MET-to-PSTN/PN calls utilize 10 digit dialing, international dialingand dialing access to operators, carriers, etc., as offered by theconnected PSTN/PN.

All dialed numbers are subject to screening based on the VN rules andthe screening associated with the individual MET. In VN-C (for dual-modeMETs registered in the MSS) registered dual-mode METs shall use theirusual PSTN number.

For each VN, it is possible to define call screening (call barring)rules (restrictions and allowances) for every MET in the VN. Screeningrules for MET originated calls are definable to govern the allowance ofa call originating at every MET in the VN. Screening rules are definableto govern the acceptance of a call presented to every MET in the VN. Inaddition to screening rules defined for all METs in the VN, screeningrules are separately definable for individual METs within the VN.

For MET-originated calls, the following general rules are availablebased on the called number.

A MET-originated call may be permitted to:

a. Any MET number in the VN.

b. No MET number in the VN.

c. Any PSTN/PN number.

d. No PSTN number.

e. Only domestic US PSTN numbers.

f. Only PSTN numbers within NPAs on a specified NPA list.

g. No PSTN numbers within NPAs on a specified NPA list.

h. Only to MET and/or PSTN/PN numbers on a specified list.

Order of application of these rules shall be as indicated by thedecision tree in FIG. 23. For calls presented to METS, the followingrules are available based on the call source (when available)

A MET-presented call may be permitted from:

a. Any MET number in the VN.

b. No MET number in the VN.

c. Any PSTN/PN number.

d. No PSTN/PN number.

If calling line identification presentation is available from thePSTN/PN, a MET-presented call may be permitted from:

e. Any domestic US PSTN number.

f. Only PSTN numbers within NPAs on a specified NPA list.

g. No PSTN numbers within NPAs on a specified NPA list.

h. Only from MET and/or PSTN numbers on a specified list.

Order of application of these rules are as indicated by the decisiontree in FIG. 23. Additional call screening rules may be provided. Forexample, a MET restricted from making any outgoing call is restrictedfrom Call Transfer since that feature involves outgoing call placement.

MET Features

This section provides a description of each feature available to METusers. Availability of a feature to a specific MET depends on thecharacteristics defined for the VN in which the MET is a member and thecharacteristics defined for the individual MET.

Connected Line Identification Presentation (COLP) is a service that isoffered to the calling MET to provide presentation of the connectedMET's number (when the call is established) to the calling MET. The GWSis capable of providing at least 10 digits for MET-terminated calls andat least 15 digits for PSTN/PN-terminated calls to the calling MET.

COLP is provisioned on a subscription basis collectively to each METswithin the VN. COLP is withdrawn on request by the subscribing authorityor by MSS for administrative reasons. COLP is active on subscription andinactive on withdrawal. COLP is automatically invoked by the GWS at callcompletion. When COLP is allowed and active, the GWS provides thecalling MET with the connected MET VN number at call completion (answer)for all MET-originated incoming calls.

When COLP or equivalent service is provided by the PSTN/PN, and theconnected PSTN/PN number is provided by the PSTN/PN, the GWS providesthe calling MET with the connected PSTN/PN number at call completion(answer) for all PSTN/PN-completed calls. When COLP is allowed andactive, the connected number is not presented if:

a. The connected MET has COLR activated, or

b. The connected number is not available from the PSTN/PN.

Assume that a user A has an established call with user B and transfersthis call with user B to user C. If user A has activated COLP, user Areceives B's number when user A evokes the normal call transferprocedure. If user C has activated COLP, user C receives B's number atthe transfer of user B to user C. A conference controller who has COLPactivated is presented with the connected party's number when that partyis either part of the initial activation of the conference or is addedto an existing conference.

If the connected party has activated Connected Line IdentificationRestriction the connected number is not presented to the calling party.If the incoming call from a MET with COLP activated has been forwarded,the number presented to the calling party is the number of the final"forwarded to" party.

Connected Line Identification Restriction (COLR) is a service that isoffered to the connected MET to restrict presentation of the connectedMET's number to the calling MET or to the PSTN/PN. COLR is provisionedon a subscription basis collectively to each MET in the VN and/orindividually to METs within the VN. COLR is withdrawn on request by thesubscribing authority or by MSS for administrative reasons. COLR isactive on subscription and inactive on withdrawal.

When COLR is allowed and active, the GWS does not provide the callingMET with the connected MET VN number for all MET-originated calls. WhenCOLR is allowed and active, no connected MET number is provided to thePSTN/PN for any PSTN-to-MET calls.

Assume that a user A has an established call with user B and transfersthis call with user B to user C. If user B has activated COLR, user Areceives B's number when user A evokes the normal call transferprocedure. If user B has activated COLP, user C receives B's number atthe transfer of user B to user C. If potential conferees have COLRactivated, the conference controller is not presented with the connectedparty's number when that party is either part of the initial activationof the conference or is added to an existing conference.

If the connected party has activated Connected Line IdentificationRestriction (COLR), the connected number is not presented to the callingparty. If the incoming call from a MET with COLP activated has beenforwarded, and the "forwarded to party has COLR activated, the"forwarded to" party's number is not presented to the calling party.

The intent of sub-addressing is to allow the identification of separateports and connected device that may be part of a MET. Examples includevoice, facsimile and data ports/devices. Each usable port on a MET shallbe assigned an VN number. The implication is that a MET port that isphysically present but does not have an assigned number cannot be used.In the following, the term "MET sub-address(s)" is used to describe oneor all of the set of (complete) VN numbers assigned to the ports of agiven MET.

The general model adapted for the subaddressing description is a PBXtelephone with multiple extensions associated with it. For example, aresult of this model is that the various MET subaddresses can beforwarded separately--this (and other) results are appropriate formulti-device (multi-media) METs.

Subaddressing is provisioned and number assigned on a subscription basisindividually to METs within the VN. Subaddresses is withdrawn on requestby the subscribing authority or by MSS for administrative reasons.Subaddressing is active on subscription and inactive on withdrawal.

Features are subscribed to and activated for each MET subaddressseparately (e.g., forwarding). It is assumed that some features (e.g.,Forwarding, Hold, Transfer) will have utility for non-voice calls.Others are precluded by the nature of the communication devices (e.g.,Conferencing, Call Waiting). For call completion purposes, a MET isconsidered busy if any MET subaddress is busy. Forwarding applies toeach MET subaddress separately. However, for Call Forwarding Busy, thebusy state applies as in 2 above.

Call Forwarding No Reply is interpreted to apply to a MET port that hasa MET subaddress assigned but no device connected. In-channel CallWaiting indication is applicable to voice ports/devices only. NumberIdentification features shall apply to each MET subaddress separately.For example, CLIP can be activated for some MET subaddresses and notothers. Call screening rules shall be definable for each subaddressseparately.

The Call Transfer (CT) feature enables a MET user (the "served user" or"AA") to transform an established call into a new call between the otherparty on the established call (user "B") and a third party (user "C").The "normal" Call Transfer procedure is offered as a feature to METusers. The GWS may offer an additional "single step" Call Transferprocedure (see below) to MET users.

"Normal" call transfer (sometimes called "screened transfer")establishes a call between the served user and the third party that maybe subsequently transformed into a call between the other party and thethird party. Optionally, the GWS may offer "single step" ("unscreened")transfer where the transfer occurs without an established call betweenthe served user and the third party.

CT is provisioned on a subscription basis collectively to each MET inthe VN and/or individually to METs within the VN. CT is withdrawn onrequest by the subscribing authority or by MSS for administrativereasons. Each of the CT types offered is subscribed to separately. The"normal" call transfer procedure shall normally operate as follows:

a. An established call exists between A and B.

b. A invokes the "normal" CT procedure, providing the number for C.

c. B shall be placed on hold and a call shall be established between Aand C.

d. During the established call, A invokes completion of the "normal" CTprocedure.

e. B shall be connected to C; connection are removed between A and theother parties.

If, during the "normal" CT procedure, the call to C cannot beestablished, A shall be able to retrieve the connection to B. The"single step" call transfer procedure, if offered, normally operates asfollows:

a. An established call exists between A and B.

b. A invokes the "single step" transfer procedure, providing the numberfor C.

c. A call is established between B and C. A is disconnected.

After the "single step" CT procedure has been invoked, B is consideredthe originating party of the attempted call to C; for example, B isinformed of alerting at C and, if the call to C cannot be completed, Bis informed.

Call forwarding allows the served or "forwarding" user to direct the GWSto send incoming calls to the served MET number to other numbers underspecific conditions. Call Forwarding Unconditional (CFU) allows theforwarding user to direct the GWS to send all incoming calls to anothernumber. Call Forwarding Busy (CFB) allows the forwarding user to directthe GWS to send incoming calls to another number if the forwardinguser's MET is in the "busy" state (establishing a call or involved in anestablished call, on hold or invoking a feature).

Call Forwarding Congestion (CFC) allows the GWS to send incoming callsto a recorded announcement if the forwarding user's MET cannot beconnected to MSS congestion. Call Forwarding No Reply (CFNR) allows theforwarding user to direct the GWS to send incoming calls to anothernumber if the forwarding user doe not reply within a subscribed timeinterval.

Forwarding is provisioned on a subscription basis collectively to eachMET in the VN and/or individually to METs within the VN. Forwarding iswithdrawn on request by the subscribing authority or by MSS foradministrative reasons. Each of the forwarding types offered issubscribed to separately. MSS may offer forwarding in "packages"containing one or more forwarding types.

The served user is able to activate each of the forwarding types offeredseparately. Activation of forwarding requires the served user to supplythe forwarded-to number. The GWS validates the forwarded-to number tothe extent possible before activating forwarding. When forwarding isactive and forwarding conditions are met, forwarding is automaticallyinvoked; incoming calls to the served user's MET is forwarded withoutbeing offered to the served user's MET.

A configurable limit is provided on the maximum number of forwardinginvocations that result from a single original call. This is intended toprevent "infinite forwarding." The GWS may provide notification to theserved user's MET when forwarding takes place. When a call is forwarded,the forwarded-to MET is provided an indication that the incoming call isoffered as a result of forwarding. The GWS provides the originallycalled number and the condition for the last forwarding operation to theforwarded-to MET.

The GWS provides notification to the calling user that the call has beenforwarded. The GWS provides the capability for the served user to reviewthe MET's forwarding status. The forwarding user's MET optionallyreceives an indication that an incoming call has been forwarded. Thismay involve a separate subscribed service.

Call waiting (CW) is a service that is offered to a called MET thatprovides that MET indication of an incoming call, if busy. If it can bedetermined that the active call is a voice call, in-channel indication(tone) is provided. Otherwise, in-channel indication is not be provided.The number of waiting calls at a busy MET is limited to one. Additionalincoming calls receive busy indication.

CW is provisioned on a subscription basis collectively to each MET inthe VN and/or individually to METs within the VN. CW is withdrawn onrequest by the subscribing authority or by MSS for administrativereasons. CW is active on subscription and inactive on withdrawal. Aprocedure is provided to allow activation or inactivation on acall-by-call basis.

CW is invoked by the GWS automatically when a call is presented to abusy MET unless a waiting call exists at that MET. The MSS network maynot be aware of the state where the MET users is entering digits for acall but has not yet invoked "send." During this state call attempts mayring rather than invoke CW or busy forwarding. Call ForwardingUnconditional takes precedence over CW. CW takes precedence over CFB. CWis presented if the called MET has CFNR activated.

The Call Hold (CH) service allows a served MET user to interrupt anexisting active call and subsequently resume (retrieve) the active call.The bearer channel remains assigned to the served user to allow theorigination or termination of other calls. The retrieve re-establishesthe original (held) call on the bearer channel. CH is provisioned on asubscription basis collectively to each MET in the VN and/orindividually to METs within the VN. CH is withdrawn on request by thesubscribing authority or by MSS for administrative reasons. Call Hold isinvoked by the served MET user by use of a control procedure.

The served user has the capability to invoke or hold any time after acall has been answered and before call clearing has begun. Call Holdallows either MET or both METs in an active call to invoke Call Hold.That is, it is possible for each party to have the other on hold. If auser invokes hold while held and makes an additional call, a new channelwill be assigned.

Provision shall be made for providing the held MET user with in-channelindication ("comfort" tone, music, etc.) that the held state persists.This indication will also inform the user who retrieves a held call thathas been placed on hold by the other party. If a MET becomes idle with acall on Hold, an indication is provided to that MET that the callremains on Hold.

Conference Calling (CONF) is a service that provides the served MET userthe capability to establish simultaneous communications with more thantwo and up to five parties. Since MET voice traffic is presented to theGWS in a packetized, compressed encoding, it is not required that theGWS provide the capability to conference more than one MET. Thus, GWSprovides the capability for conferencing among a single MET and up tofive PSTN/PN parties.

CONF is provisioned on a subscription basis collectively to each MET inthe VN and/or individually to METs within the VN. CONF is withdrawn onrequest by the subscribing authority or by MSS for administrativereasons. CONF is active on subscription.

CONF is invoked by the served MET user by use of a control procedure.The served user has the capability to request the conference as a newcall or request that the conference be based on existing held calls. Theserved user has the capability to include the maximum number ofconferees in the conference request or to accept a pre-defined default.Upon completion of the conference request, a conference is establishedamong the served MET and the other parties.

After the initial conference establishment, the served user (theconference controller) has access to the following party managementfunctions:

a. Add new party--the conference controller has the capability to add aheld call or establish a new call which may be added to the conference.

b. Drop party--the conference controller has the capability to removeconferees from the conference. If the conferee is not explicitlyidentified, the last party added is removed. If, after the party isdropped, a single conferee remains, the GWS may establish a two-partycall.

c. Split party--the conference controller has the capability to remove aspecified party from the conference and establish an active (two-party)call with the specified party. From the perspective of the conferencecontroller, the conference is on Hold. The conference controller has thecapability to resume the conference after a split (i.e., return bothparties to the conference).

A mechanism for supplying Conferee IDs for conference managementfeatures above (e.g., dropping a specific conferee) is provided. Theconference controller has the capability to disconnect the conference.All conferees and the conference controller are dropped and theconference resource (bridge) is released.

Alternate Account Charging (AAC) allows a MET user to charge a call toan account other than the usual or default account. Alternate accountcharging provides the MET user the capability to supply an AlternateAccount Number during call setup request. GWS records the AlternateAccount number in the CDR. GWS is not required to verify or otherwisevalidate the Alternate Account Number.

AAC is provisioned on a subscription basis collectively to each MET inthe VN and/or individually to METs within the VN. AAC is withdrawn onrequest by the subscribing authority or by MSS for administrativereasons. AAC is activated upon subscription. AAC is optionally invokedby the MET user at call setup request. The invocation includes theAlternate Account Number.

Call Queueing and Priority (CQP) are intended to be applied toMET-originated calls in the event of MSS network congestion. Note thatthe management of satellite resources is a function of the MSS NetworkControl Center (NCC) and not a function of the GWS. However, uponnotification of satellite resource congestion by the NCC (via the SLSS),the GWS queues calls affected by that congestion. Similarly, uponnotification by the NCC that congestion no longer exists, the GWSattempts to service queued calls as detailed below.

Priority and queueing are not intended to be applied in the event of abuy MET. Call Priority and Queuing may also occur as a result ofcongestion for PSTN/PN access. Congestion of MSS satellite signallingchannels occurs as well as traffic channel congestion. Signaling accessqueueing occurs external to the GWS.

GWS supports traffic access queueing for MET-originated calls whentraffic congestion is indicated by MSS. Determination of satellitecongestion conditions is not a function of the GWS. GWS supports trafficaccess queueing for MET-originated calls when PSTN/PN access congestionexists. Traffic access priority is assignable to a VN and to individualMETs. Call setup requests are queued under congestion conditions and areprocessed first-in, first-out within individual priorities.

CQP is provisioned on a subscription basis collectively to each MET inthe VN and/or individually to METs within the VN. CQP is withdrawn onrequest by the subscribing authority or by MSS for administrativereasons. Specification of priority accompanies subscription. CPQ isactive on subscription. If CQP is not subscribed to, calls receive acongestion indication but will not be queued.

CQP is invoked automatically by GWS upon indication of satellitecongestion by the SLSS or detection of PSTN/PN access congestion by GWS.If CPQ is invoked, GWS provides the calling MET indication of congestionand queueing. When congestion is relived, GWS serves queued callsaccording to priority as follows:

a. Originating a call to the MET that originated the queued call.

b. If this call is successful, GWS shall execute call setup proceduresfor the queued call.

Virtual Network Manager

Virtual Network Manager controls user access to a designated virtualnetwork and its service features, provides communication circuits amongmember users on a call-by-call or full period basis, and manages acustomer virtual network. The Virtual Network database entries for agiven network shall specify the type of services, network features andcall routing options that are available for use by member METs and FESs.Virtual Network Managers interact only with member METs an FESs.

The Virtual Network Management function interfaces with the GroupResource Management function and the Network Access processing functionto carry out its responsibilities to receive call requests and issuesatellite circuit assignments, to request, receive and return satellitecircuits from/to the CG circuit pool, to return preempted circuits, andto transmit call records following each call cleardown.

To provide service connections for customers, Virtual Network Managementprovides functions for connection period control, call processing, callrouting, circuit configuration, address screening, emergency preemption,and resource utilization auditing. The Virtual Network Manager maintainsa record of which GC managed features are active. Features which areactivated by subscription are active and perform the actions specifiedbelow for each active feature.

The GC supports VN configurations for virtual network service consistingof a set of METs, each with a MET Database File, and a set of virtualnetwork communication groups, each assigned a VN ID with a VN IDDatabase File. The GC performs VN Management for each call request. EachGC supports multiple customer virtual network configurations inaccordance with the virtual network definition.

As each MET or FES originated access request is received, the GCidentifies which Virtual Network is being accessed, according to theprocedures specified below, and utilizes the associated Virtual Networkdatabase and the Customer Configuration database to process and servicethe request. Virtual Network management is performed for each callrequest in accordance with the call processing specifications.

The GC supports the provision of advanced service features to MET. WhenCall Forwarding or Call Waiting has been activated the following VirtualNetwork call processing requirements for basic service shall besuperseded at the appropriate points in the protocols.

The following describes the Virtual Network process requirements in thecontext of FIG. 24 which is a more detailed illustration of the NCCterminal equipment. MET originated access requests received by theNetwork Access Processor are routed to the GC to which the receivingMET-SR signaling channel has been assigned by the NCC Controller. The GCtakes the following actions based on the GC operational state.

    ______________________________________                                        GC Operational State                                                                           MET Request Disposition                                      ______________________________________                                        Inactive/Initialized                                                                           Discard all requests                                         Active - Normal  Process all requests                                         Active - Unloading                                                                             Block new "Access Requests"                                  Services         with "Call Failure"                                                           not available Discard all                                                     other requests                                               Active - Unloaded                                                                              Block new "Access Requests"                                  Service          with "Call Failure"                                                           not available Discard all                                                     other requests                                               ______________________________________                                    

In the Active--Normal state the GC examines the "Access Request" messageto determine whether a Virtual Network identifier has been transmittedby the MET along with the dial digits. If a Virtual Network identifierhas not been included in the request, the GC determines the METs defaultVirtual Network from the Customer Configuration database. If aparticular Virtual Network has been requested, the GC utilizes thecustomer Configuration database to convert the logical Virtual Networkidentifier of the message to the internal Virtual network identifier.The GC then takes the following actions based o the Virtual Networkoperational state.

    ______________________________________                                        Virtual Network                                                               Operational State                                                                              MET Request Disposition                                      ______________________________________                                        Inactive/Initialized                                                                           Discard all requests                                         Active - Normal  Process all requests                                         Active - Unloading                                                                             Block new "Access Requests"                                  Service          with "Call Failure"                                                           not available Discard all                                                     other requests                                               Active - Unloaded                                                                              Block new "Access Requests"                                  Service          with "Call Failure"                                                           not available Discard all                                                     other requests                                               ______________________________________                                    

FES originated channel requests received by the Network Access Processorare routed to the NCC Controller, based on the message destinationaddress. FESs will address channel requests to the NCC Controller so theMET Control Group membership can be determined. The NCC Controlleraccesses the Customer Configuration database, using the MET telephonenumber dial digits included in the FES "Channel Request" message, anddetermines the identity of the GC to which the MET belongs. The NCCController then forwards the message to the identified GC. The GC shalltake the actions as specified above based on the GC operational state.

In the Active--Normal state the GC accesses the Customer Configurationdatabase, using the MET telephone number dial digits included in the FES"Channel Requests" message, and determines the identity of the VirtualNetwork which is being accessed. The GC then takes the actions specifiedabove based on the Virtual Network operational state.

Whenever the NCC Controller determines that the GC cannot besuccessfully identified in the databases using received access signalingdata, the access request is denied. Whenever the GC determines that acalled or calling MET is registered but the Virtual Network cannot besuccessfully identified in the databases using received access signalingdata, the access request is denied. When calls are so denied, a "CallFailure" message with the cause set to "Service not Subscribed" is sentto the requesting MET or FES, and the call data record is terminatedwith the cause indicated.

Upon successful identification of the Virtual Network serving the accessrequest, the GC processes calls, using the associated Virtual Networkdatabase, in accordance with the Virtual Network management requirementsspecified in the following sections. Whenever a call record for anaccess request is terminated for any reason, the appropriate VirtualNetwork performance statistic is updated.

Access request processing consists of call screening actions using theCustomer Configuration and Virtual Network databases, and the MET StatusTable, to determine whether the requested service is a valid subscribedservice for the MET and the Virtual Network, and whether the MET statusis in a call state compatible with the access request. In performancesof MTS access request processing, the GC processes dial digits for PSTNusers in accordance wit the PSTN numbering plan. In performance of MRSaccess request processing the GC accommodates independent numberingplans, using fewer dial digits than the PSTN plans, which will beutilized by each private Virtual Network.

Upon each MET or FES access request, the GC evaluates the securityauthentication history for the associated MET. If a configurable numberof authentication failures have occurred within a configurable timeperiod from the time of access, the call is denied.

MET to Terrestrial Network Connection Requests

In processing MET originated call requests, the GC receives MET "AccessRequest" and "Additional Digits" messages, and shall transmit"Additional Digits Request" and/or "Call Failure messages when required.Upon receiving a MET "Access Request" the GC accesses the MET StatusTable using the RTIN to verify the calling MET is in the "Operational"state and whether the MET is currently engaged in a call. The identityof the MET-SR channel receiving the request is used by the GC to verifywhether the MET is currently logged on to correct L-Band beam asindicated in the MET Status Table.

Log-on errors result in a PVT for the MET with the event and resultssent to the NOC and noted as anomalous events. When the PVT issuccessful the MET is logged on to the associated beam. If the MET isnot in the "Operational" state the GC terminates the call record andsends a call failure message to the MET with the reason set to "Servicesnot Available". If the MET is operational, the GC accesses the METStatus Table to evaluate the current MET call state.

If the MET call state indicates the GC is currently awaiting circuits ora MET call announcement response, for a prior FES channel request, theGC shall abandon the prior FES request in favor of the new MET accessrequest, terminate the call record with the reason set to "Glare" andsend a call failure to the FES with the cause set to "MET Busy". The GCshall proceed to process the MET "Access Request" as further describedin this subsection.

If the MET state indicates the MET is engaged in a call-in-process, thereason is declared as an anomalous condition, the MET is sent a callfailure message with "Network Busy" as the cause and the current callrecord is terminated with "Calling MET Busy--Anomaly" as the reason. TheGC then immediately initiates a call auditing action to resolve theanomalous condition existing for the prior call. This action will clearthe MET status and network resources so that subsequent service requestsby the MET will be accommodated.

When a requesting MET is operational, and in the "MET Idle" call state,the GC collects additional dial digits as necessary, access the ControlGroup Customer Configuration data base and determine, based on thedestination dial digits, whether the called destination is a MET user.If the destination is not identified in the Customer Configurationdatabase as a MET user the GC declares the destination to be aterrestrial user. The GC accesses the operative Virtual NetworkConfiguration database and performs the following Virtual Networkservice permission and address screening checks:

a. The type of service requested (voice/2.4 kbps data/4.8 kbpsdata/fax/alternate voice-data) is supported by the Virtual Network.

b. If the Virtual Network is configured with an explicit set ofterrestrial user member telephone numbers, and the destination telephonenumber is included in the member list, then the call is permitted.

c. Outgoing calls permitted.

d. MET to terrestrial network calls permitted.

e. International calls permitted.

f. Calls to the specific destination NPA are permitted.

If the Virtual Network address screening and service permission checkspass, the GC accesses the Customer Configuration database using the RTINand the destination dial digits, and perform the following MET addressscreening and service permission checks:

a. The type of service requested (voice/2.4 kbps data/4.8 kbpsdata/fax/alternate voice-data) is authorized for the MET.

b. Outgoing calls permitted.

c. MET to terrestrial network calls permitted.

d. International calls permitted.

e. Calls to the specific destination NPA are permitted.

f. If the MET is part of a VN group, the destination telephone number isa VN group member.

If all MET and Virtual Network address screening and service permissionrouting checks are successful, the GC updates the call record with theappropriate data and perform the call routing process. If a MET orVirtual Network address screening check or service permission check isunsuccessful, the GC terminates the call record upon finding the firstcheck failure, and sends the MET a call failure message with the causeindicated as "Service not Subscribed". The call record encodes thespecific failed check resulting in termination.

Terrestrial Network to MET Connection Requests

In processing terrestrial network originated call requests, the GCreceives FES "Channel Request" messages, and transmits "Call Failure"messages. Terrestrial network access requests are preprocessed by theNOC Controller to identify the GC serving the called MET. Upon receivinga FES "Channel Request," the GC first evaluates the channel requestmessage to determine whether this request is for the FES-to-destinationMET connection of a MET to MET call.

If the request is not for a MET to MET connection, the GC accesses theMET Status Table, using access data provided by the NCC Controller, toverify the called MET is in the "Operational" state and whether the METis currently engaged in a call-in-progress. If the MET is not in the"Operational" state, the GC terminates the call record and sends a callfailure message to the FES with the reason set to "Service notAvailable". If the MET is operational and the MET call state is anystate other than idle, the GC terminates the call record and sends acall failure message to the FES with the cause set to "MET DestinationBusy"

If the MET is operational and not currently engaged in an active callstate, the GC accesses the MET Status Table and evaluates the accessevent history data for recent unsuccessful call announcements. If therehave been a configurable number of unsuccessful call announcementswithin a configurable time limit, from the current time, the GC sends acall failure message to the FES with the reason set to "MET DestinationNot Available". The call record is terminated with "Excess MET Pages" asthe reason.

When the called MET is operational, not engaged in an active call state,and an acceptable number of unsuccessful call announcements have beenplaced to the MET, the GC accesses the operative Virtual NetworkConfiguration database and perform Virtual Network address screening andservice permission checks:

a. The type of service indicated by the MET destination port (voice/2.4kbps data/4.8 kbps data/fax/alternate voice-data) is permitted.

b. Incoming calls permitted.

c. Terrestrial network to MET calls permitted.

d. International calls are permitted (if the calling number isprovided--otherwise connection is permitted by default).

e. The calling NPA is permitted (if NPA restrictions apply and thecalling number is provided--otherwise connection is permitted bydefault).

f. If the MET is part of a closed user group (CUG), and the originationtelephone number is both provided and recognized as a CUG member, thenthe call is permitted. If the calling number is not provided theconnection is permitted by default.

If all MET and Virtual Network address screening and service permissionrouting checks are successful, the GC updates the call record with theappropriate data and perform the call routing process. If an MET orVirtual Network address screening and service permission routing checkis unsuccessful, the GC terminates the call record upon finding thefirst check failure, and sends the FES a call failure message with thecause indicated as "Service not Subscribed". The call record encodes thespecific failed check resulting in termination.

MET to MET Connection Requests for Originating MET

If the destination is identified by the dial digits as a MET user, theGC accesses the Customer Configuration database and determines if thedestination MET is subscribed with membership in the Virtual Networkbeing accessed by the origination MET. If the origination anddestination METs are members of the Virtual Network being accessed bythe origination MET, the GC performs Virtual Network service permissionand address screening checks for the destination MET using its VirtualNetwork Configuration databases.

After identifying the proper Virtual Network database(s) the GC accessesthe MET Status Table and verify the destination MET is operational andnot engaged in an active call state. If the destination MET is notoperational the GC terminates the call record indicating "DestinationMET not Available". If the destination MET is in any call state otherthan idle, the GC terminates the call record indicating "Destination METBusy", and the originating MET a call failure message with the causeindicated as "Destination MET Busy".

If the destination MET is operational and idle, the GC sets a MET to METcall pending flag in the destination MET status entry of the MET StatusTable, accesses the MET Virtual Network Configuration database(s) andperforms the following Virtual Network address screening and servicepermission checks:

a. The type of service requested (voice/2.4 kbps data/4.8 kbpsdata/fax/alternate voice-data) is supported by the origination anddestination Virtual Networks.

b. MET to MET calls permitted.

c. Incoming calls permitted for the destination Virtual Network

d. Outgoing calls permitted for the originating Virtual Network.

e. Calls to any Virtual Network permitted by the origination VirtualNetwork.

f. Calls to selected Virtual Networks permitted and the destinationVirtual Network is in the permitted set.

If the Virtual Network service permission and address screening checkspass, the GC accesses the Customer Configuration database using the FTINof the origination and destination METs and performs the following METaddress screening and service permission checks for the originating MET:

a. The type of service requested (voice/2.4 kbps data/4.8 kbpsdata/fax/alternate voice-data) is authorized for the MET.

b. Outgoing calls permitted.

c. MET to MET calls permitted.

d. Calls to any Virtual Network permitted.

e. Calls to selected Virtual Networks permitted and the destinationVirtual Network is in the permitted set.

If the originating MET address screening and service permission checkspass, the GC performs the following MET address screening and servicepermission checks for the destination MET:

a. The type of service requested (voice/2.4 kbps data/4.8 kbpsdata/fax/alternate voice-data) is authorized for the MET.

b. Incoming calls permitted.

c. MET to MET calls permitted.

If all MET and Virtual Network address screening and service permissionrouting checks are successful, the GC updates the call record with theappropriate data and performs the call routing process. If an MET orVirtual Network address screening check or service permission check isunsuccessful, the GC terminates the call record upon finding the firstcheck failure, and sends the MET a call failure message with the causeindicated as "Service not Subscribed". The call record encodes thespecific failed check resulting in termination.

MET to MET Connection Requests for Destination MET

Upon receiving a FES "Channel Request" that indicates aFES-to-destination MET connection is being requested for a MET to METcall, the GC generates a separate call record for the Destination METusing the "Call Identifier" previously assigned during the originatingMET call setup and provided in the request message. The call recordincludes MET ID data needed to complete the connection to thedestination MET. The GC proceeds to route the call.

Call Routing

When a GC successfully completes MET and Virtual Network addressscreening and service permission checks for access requests, the GCattempts to route the call using the routing rules and the VirtualNetwork Routing database. The routing process selects:

a. The FES Terminal Equipment that will support a MET to terrestrialnetwork call, or

b. The FES Terminal Equipment and destination MET port that will supporta MET to MET call, or

c. The MET port that will support a terrestrial network to MET call.

The GC reports both MTS and MRS routing configurations. The GCaccommodates, in any proportion, different routing rules for each memberof a set of individual Virtual Networks and accommodates common routingrules for selected sets of one or more Virtual Networks.

MET to Terrestrial Connection Routing

To route a MET call to the terrestrial network, the GC accesses theVirtual Network Routing database and selects the FES Terminal Equipmentbased upon the destination dial digits. Each MTS Virtual Network Routingdatabase is configured such that a variable number of the first n dialdigits are processed to select the FES Gateway. The first n dial digitsare comprised of the following:

a. Domestic call or destination country code for internationalcalls--[x] digits.

b. The destination NPA--3 digits.

c. The local exchange within the NPA--3 digits.

For MTS it is possible to associate each set of `n` dial digits with anordered set of FES Gateway entries. The FESs is arranged in the order ofpreference for routing. The number of FES Gateway entries ranges from 1to 7.

Each MRS Virtual Network Routing database is configured such that aspecific range of numbers in the associated private numbering plan areprocessed to select a FRS Base Station. The dial digit rangesdifferentiate which FES base station is to be used. Each MRS dial digitnumber range is associated to an ordered set of FES base stationentries. The FESs is arranged in the order of preference for routing.The number of numbering plan ranges are from 1 to 16 and the number ofFES Base Station entries range from 1 to 3.

Once the GC has identified the routing FES entry set, it accesses theFES Status Table and FES Resource Pool for the most preferred FES. Itthen determines that FES's network availability and the availability ofits communication and terrestrial interface resources to support thecall. If the preferred FES is available to the network, the GC allocatescommunication and terrestrial interface resources from the pool for thecall being routed. FES resources are allocated based on the specificservice type requested by the MET.

If the preferred FES is unavailable or the communication or terrestrialinterface resources are insufficient to support the call, the GCaccesses the Customer Configuration and virtual Network Configurationdatabases to determine whether both the MET and Virtual Network areauthorized for alternate FES routing or fixed FES routing. If fixed FESrouting is required, the GC terminates the call record indicating "FESnot Available" and sends the MET a call failure message with the causeset to "Network Busy".

If the preferred FES is unavailable or communication or terrestrialinterface resources are sufficient to support the call, and alternateFES routing is authorized for both the MET and the Virtual Network, theGC sequentially repeats the procedure above for each FES in the set, indescending order of routing preference, until an available FES isidentified with sufficient resources to support the call.

When an available FES with sufficient communication and terrestrialinterface resources is identified, either under alternate routing orfixed routing procedures, the GC proceeds to allocate satellite circuitsto the call. The call record is updated to show the FES selected andwhether the alternate or fixed process was used. If alternate FESrouting is authorized but an available FES with sufficient communicationand terrestrial interface resources cannot be identified within therouting set, the GC terminates the call record indicating "FES notAvailable or Insufficient FES Resources", as appropriate, and sends theMET a call failure message with the cause set to "Network Busy"

In the event the Virtual Network Routing Table does not include anyrouting entries for the `n` dial digits included in the request message,the GC terminates the call record indicating "Routing not Provided" andsends the MET a call failure message with the cause set to "Service notSubscribed".

Terrestrial to MET Connection Routing

To route a terrestrial network to MET call, the GC accesses the CustomerConfiguration database and identifies the MET port that is associatedwith the MET's destination telephone number received in the channelaccess request message. The GC updates the FES Communication andTerrestrial Interface Status tables to reflect the resource allocationmade by the calling FES prior to signaling the channel request for thiscall. The GC proceeds to allocate satellite circuits to the call andupdates the call record to show the destination MET port ID selected.

MET to MET Connection Routing for Originating MET

To route a MET call to another MET, the GC accesses the Virtual NetworkRouting database and selects an FES Terminal Equipment from an orderedset of FESs that have been designated to service MET to MET calls.Alternate routing is assumed automatically when more than 1 FES isincluded in the ordered set. The FESs are arranged in the order ofpreference for routing. The number of FES entries ranges from 1 to 7.

Once the GC has identified the routing FES entry set, it accesses theFES Status Table for the most preferred FES, and determines the FES'snetwork availability and the availability of its communication andterrestrial interface resources to support the call. If the preferredFES is available to the network, the GC allocates MET to METcommunication resources from the pool for the call being routed. FESresources are allocatable based on the specific service type requestedby the MET.

If the preferred FES is unavailable or communication resources areinsufficient to support the call, the GC sequentially repeats theprocedure above for each FES in the set, in descending order of routingpreference, until an available FES is identified with sufficientresources to support the call. When an available FES with sufficientcommunication resources is identified, the GC proceeds to allocatesatellite circuits for the originating MET connection. The call recordis updated to show the FES selected. Subsequent FES processing generatesa channel request for the FES-to-destination MET connection.

If an available FES with sufficient communication resources cannot beidentified within the routing set, the GC terminates the call recordindicating "FES not Available or Insufficient FES Resources", asappropriate, and sends the MET a call failure message with the cause setto "Network Busy".

MET to MET Connection Routing for Destination MET

To route the FES-to-destination MET connection for a MET to MET call,the GC proceeds to allocate circuits for the destination MT connectionas specified in the MET to MET Connection Routing for Originating METSection.

Satellite Trunk Circuit Management

Only when all MET and Virtual Network service permission andconnectivity checks for an access request have passed and networkrouting facilities have been determined available and reserved, the GCselects the required forward and return link trunk circuit frequenciesand the FES forward link power level to service the call.

Each GC manages satellite trunk circuit resources using circuit pools.Channel center frequencies are identified in accordance with theseparate L-Band and Ku-Band conventions.

Circuit Allocation

The GC accesses the Customer Configuration database to determine therequired circuit configuration for the MET port which is being accessedby the call. The database indicates the bandwidth required for theforward and return links, the minimum MET frequency tuning increment,and the FES forward link power level authorization. For MET to METconnections, the GC identifies forward and return link circuitconfigurations for both the originating MET and destination MET and thefollowing circuit and power allocation processing are performed for bothMETs.

The GC accesses the origination Virtual Network Configuration databaseto determine the connectivity period class authorized: demandperiod--free pool, demand period--reserved pool, or full period. The GCaccesses the MET Status Table to identify the L-Band beam to which theMET is currently logged on. The GC then attempts to allocate therequired circuit from the proper frequency pool, based on connectivityclass and L-Band beam requirement.

The GC searches the pool to identify unused frequencies containingcontinuous spectrum sufficient to provide the MET channel bandwidthrequirement. The GC determines each resulting channel center frequencyfor inclusion in subsequent "Channel Assignment" messages. If therequired circuits are available, the authorized forward link power levelis retrieved from the Customer Configuration database for the associatedMET port and the FES nominal EIRP retrieves form the FES ConfigurationTable.

Satellite Trunked Circuit Queuing

When queuing is enabled for MET originated calls, and the requestedcircuit pool bandwidth or power resources are not immediately available,the GC accesses the Customer Configuration database to identify the METpriority associated with the Virtual network being accessed. The circuitrequest is then entered into the tail of the queuing system which isstructured with separate queuing sets for each L-Band beam being servedby the GC. The individual queues within each L-band beam queue set isallocated to each MET priority level.

Call Setup Processing

When all MET and Virtual Network service permission and connectivitychecks for an access request have passed, network routing facilitieshave been determined available and satellite trunk circuits have beensecured from the pool, the GC proceeds to the call setup procedure.

Off-Line NCC Virtual Network Updating

Each GC updates its counterpart GC in the Off-line NCC upon eachtransition of a MET call into the "MET Busy--Call in Progress" state orthe MET Operational and Idle" state. Other state transitions are notreported to the Off-line NCCTE GC. Each Virtual Network update includesall call record, MET Status Table, Circuit Pool Status Table, FESCommunication and Terrestrial Interface Pool data sets for the callbeing updated. The Off-line counterpart GC utilizes update reports tomodify its associated tables and call records to reflect concurrencywith the On-line GC. Upon NOC command to assume the On-line NCC role,the GC commences Virtual network management using the call and resourcestates at the time of switchover.

The many features and advantages of the invention are apparent from thedetailed specification, and thus, it is intended by the appended claimsto cover all such features and advantages of the invention which fallwithin the true spirit and scope of the invention. Further, sincenumerous modifications and variations will readily occur to thoseskilled in the art, it is not desired to limit the invention to theexact construction and operation illustrated and described, andaccordingly, all suitable modifications and equivalents may be resortedto, falling within the scope of the invention.

DICTIONARY ITEMS AND DEFINITIONS

Actual GSI

Definition: Current GSI based on TDM changes during MET operation. Thisfield is populated by the NOC based on actions on the CGS. The CMIScannot create or update this field.

Call Barring Inbound/Outbound Flag

Definition: Describes the call barring entry as applying to incoming oroutgoing calls. If the Call Barring List is flagged as Inbound, itapplies to calls the MET is receiving. If the Call Barring List isflagged as Outbound, it applies to calls the MET is making.

Call Barring Include/Exclude Flag

Definition: Describes the call barring entry as an included (legal) callor an excluded (illegal) call. When a Call Barring List is flagged asInclude, the MET may only make calls to the numbers or NPAs on the list.Any other call would be denied. Conversely, if a Call Barring List isflagged as Exclude, the MET may make calls to any number or NPA exceptthose on the list.

Call Barring List Value

Definition: Numbering plan area or phone number in the call barringlist. The values that appear in the list are the phone numbers or NPAsthat the MET's restriction apply to. The types of restrictions aredictated by the flags for Include/Exclude and Inbound/Outbound CallBarring.

Call Trap Flag

Definition: Indicates call trapping has been initiated for the MET. TheGC will trap MET states as they change during MET CGS activity. Thisinformation will be provided to the CMIS on a call record.

Call Type

Definition: Service available on the MET. There are four service types:voice data (2400 or 4800 baud), fax, and alternate voice data (avd). Foreach service the mobile is registered, a service record is created witha single call type indicated. This call type in turn has a unique mobileidentification number (min) associated with it.

Carrier

Definition: Name of preferred IXC carrier. This field is a switch fieldused to support equal access to long distance carriers.

Cellular ESN

Definition: 32 bit ESN that is used by the switch. For dual modecellular/satellite phones it is the ESN for the cellular portion of thephone and would match the ESN used by the home cellular carrier toidentify that mobile terminal.

CGS Time Stamp

Definition: Time stamp was created/modified. Part of the notification ofsuccess or failure of CGS action. Not created or updated by CMIS.

Channel Spacing

Definition: Multiple of frequency step size. This element is acharacteristic of the MET Class. CMIS will only have the MET Class IDthat a particular METs equipment maps to. NE originates this and otherdata that describes the MET Class and sends it to the NOC.

Check String

Definition: Constant used by the GC to validate theencryption/decryption algorithm. This element is related to the ASK.

Commanded GSI

Definition: Set by CMIS this is the original GSI stored as a NVRAM(non-volatile RAM) parameter by the MET. Required for each new METregistered for service. This element is used by the MET to tune to aGC-S channel during commissioning on the CGS. Without the GSI the MET isincapable of logging on to the CGS.

Configuration File

Definition: A file containing the contents of a working configurationthat has been saved to disk under a unique name.

Current Configuration

Definition: The set of resources that exist in the configuration mostrecently sent to or received from the NOC. This is assumed to be theactual configuration of the traffic bearing network at any given time.

Commit a Resource

Definition: Explicit engineer action to add a fully provisioned interimresource to the working configuration.

Control Group ID

Definition: The CGS is divided into Control Groups that contain circuitpools, signaling channels, bulletin boards, METs, and VNs. A MET mayonly belong to one Control Group. The control Group assignment is basedon the virtual network membership. All VNs a MET is a member of must bein the same control group.

Cust Group

Definition: Identifier for a specialized routing information used at theswitch (e.g., 1024 available cust groups per MSR). Dialing plans will beimplemented for groups of customers through a Customer Group (CustGroup).

Data Hub Id

Definition: Used to route messages during PSTN to IVDM call setup to theproper data hub. This is only applicable for METs that are participatingin the Mobile Packet Data Service.

Date Last Tested

Definition: Time stamp of most recent commissioning test. This field ispopulated by the NOC and cannot be created or updated by CMIS.

Default VN

Definition: VN selected if user does not specify VN during dialing. ForMETs that belong to only one VN, this can be populated with the VN IDthe MET is assigned to by default.

EIRP

Definition: Equivalent Isotropic Radiated Power--power level requiredfor a MET to receive a satellite signal. This element is acharacteristic of the MET Class. CMIS will only have the MET Class IDthat a particular METs equipment maps to. NE/SE originates this andother data that describes the MET Class and sends it to the NOC.

Event Argument Id

Definition: Part of the Event Record received from the NOC. CMIS has nopart in creating or updating events-they arrive unsolicited from theNOC.

Event Argument Type

Definition: Part of the event Record received from the NOC. CMIS has nopart in creating or updating events-they arrive unsolicited from theNOC.

Event Argument Value

Definition: Part of the Event Record received from the NOC. CMIS has nopart in creating or updating events-they arrive unsolicited from theNOC.

Event Argument VMS Type

Definition: Part of the Event Record received from the NOC. CMIS has nopart in creating or updating events-they arrive unsolicited from theNOC.

Event Code

Definition: Part of the Event Record received from the NOC. CMIS has nopart in creating or updating events-they arrive unsolicited from theNOC.

Event Severity

Definition: Network impact assessment of the trouble event.

Event Time

Definition: Time the event occurred within the network.

Event Type

Definition: Part of the Event Record received from the NOC. CMIS has nopart in creating or updating events-they arrive unsolicited from theNOC.

External Date Time Stamp

Definition: CMIS generated time stamp used for CMIS audit purposes inexchanging messages with the CGS.

External Transaction Id

Definition: CMIS generated transaction id used for CMIS audit purposesin exchanging messages with the CGS.

Feature Set

Definition: Identifies MET features within a specific VN. Fixed featuresare set up during order processing and require no action by the MET userto invoke a feature. MET activated features must also be set up duringorder processing but will only be available through some action on thepart of the MET use during call process.

FIXED FEATURES include:

Calling Line Id Presentation (CLIP)--display the calling party's numberto a MET.

Calling Line Id Restriction (CLIR)--prohibition from displaying the METsnumber when it is calling another party.

Connected Line Id Presentation (COLP)--display the number the callingMET is connected to.

Connected Line Id Restriction (COLR)--prohibit display of the connectedMET's number to the calling party.

Sub-addressing (SA)--allows one or more attachments to the MET to beaddressed. This is being accomplished through unique phone numbers forservice types requiring different equipment.

Call Waiting (CW)--notification to a MET engaged in the call thatanother call is waiting. MET may accept the other call or ignore it.

Call Barring (CB)--restricts the MET user's from making or receiving oneor more types of calls.

Operator intervention (OI)--allows an operator to break into a call inprogress for the MET.

Operator Assistance (OA)--allows the MET to access an MSAT operator toreceive assistance

Call Priority (CP)--used in conjunction with the system's call queuingfunction (trunk access priority) presence of this feature gives a METaccess to channels at times of congestion ahead of MET's with lowerpriority. Priority applies only to MET initiated calls.

MET ACTIVATED (dynamic) FEATURES include:

Call Transfer (CT)--allows sa MET user to transfer an established callto a third party.

Call Forwarding Unconditional (CFU)--permits a MET to have all callsforwarded to another MET or PSTN number.

Call Forwarding Busy (CFB)--permits a MET to have all incoming callsattempted when the MET is busy to another MET or PSTN number.

Call Forward Congestion (CFC)--permits the MET to have all incomingcalls attempted when the signaling channels are congested answered witha recorded announcement intercept.

Call Forward No Reply (CFN)--permits a MET to have all incoming callsattempted when the MET is not answering to another MET or PSTN number.This applies if the MET is blocked, turned off or not answering.

Call Holding (CH)--allows a MET to interrupt call communication on anexisting connection and then re-establish communications.

Alternate Voice Data Operation (AVD)--allows a MET user to togglebetween voice and data mode during a call. Requires that the call beinitiated in voice mode. Only the MET user may toggle between voice anddata. This requires a special service type in addition to the activationat set-up of the feature.

Conference calling (CC)--allows a MET to communicate withmultiple-parties including METs and PSTN concurrently.

Three Party Service (3PS)--allows a MET to who is active on a call tohold that call, make an additional call to a third party, switch fromone call to the other (privacy being provided between the calls) and/orrelease one call and return to the other.

Malicious Call Trace (MCT)--enables an MSAT operator to retrieve thecomplete call record at a MET's request for any terminated call inreal-time. The operator can then identify the calling party to the METand take appropriate action.

Voice Mail (VM)--allows call forwarding to a voice mail box andretrieved of messages by the MET.

Alternate Accounts Charging (ACC)--allows the MET user to enter in anaccount code to charge the call to after entering the dialed digits

Fully Provision

Definition: Supply values to all attributes of a resource

Frequency Step Size

Definition: Minimum tuning increment acquired for a MET to tune in anassigned channel. CMIS will only have the MET Class ID that a particularMET's equipment maps to. NE originates this and other data thatdescribes the MET Class and sends it to the NOC.

From MET Call Barring Flags

Definition: Describe actions available to a user originating a call froma MET. These call Barring flags relate to specific types of calls at anaggregate level to indicate if the MET can make or receive a call of aparticular type. When this list indicates that an Inclusion or Exclusionto particular numbers or area codes is allowed, the values for thoserestrictions are indicated on a Call Barring List.

FTIN

Definition: Forward Terminal Identification Number--Downloaded to METfrom NOC during commissioning. Used for MET to GC signaling.

Internal Data Time Stamp

Definition: NOC generated time stamp used for NOC audit purposes.

Internal Transaction Id

Definition: NOC generated transaction is used for NOC audit purposes.

Interim resource

Definition: The resource currently being modified by the engineer.Changes made to an interim resource are not added to the workingconfiguration until the resource is committed to the workingconfiguration

L Band Beam

Definition: Current beam MET is logged into. Determined by the GC duringcommissioning. CMIS has no role in creating or updating this field.

LCC

Definition: Line Class Code--type of phone, required by the switch.

MCC Class Id

Definition: Part of the Event Record received from the NOC. CMIS has nopart in creating or updating events--they arrive unsolicited from theNOC.

MCC Instance

Definition: Part of the Event Record received from the NOC. CMIS has nopart in creating or updating events--they arrive unsolicited from theNOC.

MCC Instance Id

Definition: Part of the Event Record received from the NOC. CMIS has nopart in creating or updating events--they arrive unsolicited from theNOC.

MCC Instance Type

Definition: Part of the Event Record received from the NOC. CMIS has nopart in creating or updating events--they arrive unsolicited from theNOC.

Message Status 1

Definition: Used in the message initiated by the NOC to acknowledgesuccess or failure of a previously transmitted CMIS request. Used by theDM.

Message Status 2

Definition: Used in the message initiated by the NOC to acknowledgesuccess or failure of a previously transmitted CMIS request. Will beused by the DM.

Message Verb

Definition: Action required at the NOC on data passed in a message fromCMIS. This field is in the message relaying the results of a CMISrequest.

Modulation Scheme

Definition: Non-standard modulation schemes. CMIS will only have the METClass ID that a particular MET's equipment maps to. NE/SE originatesthis and other data that describes the MET Class and sends it to theNOC.

MSA

Definition: Mobile Servicing Area--identifies the last call's servicingarea. Atomic data element within MSR. Transient data maintained in callprocessing not on the cellular switch table. Same as MSR.

MSR

Definition: Mobile Servicing Region id (table) contains multiple MSAassignments for the MET. For a roamer, the operator will input the MSRfor temporary assignment. Allows up to 1024 cust groups--At CGS startupthere will be 1 MSR.

MET ASK

Definition: Access Key MET must match during call setup/validation.

MET Class ID

Definition: Identifies the operating characteristics of the MET.Associated to MET by CMIS during registration from data supplied byNE/SE. The technical characteristics the MET Class ID encompasses arenot needed by CMIS. These are stored on a table in the NOC andreferenced by having the ID on the MET Information record. This IDapplies to MET level regardless of how many services, etc. the MET hastied to it.

MET Commanded State

Definition: Current CGS status of MET.

MET Fraud Flag

Definition: Indicates fraud has been detected on the MET. Updated by GCand CMIS only. This field is set at the MET level regardless of thenumber of services, etc. the MET has.

MET ID

Definition: CMIS assigned unique MET identifier. This can be a uniquerandom number assigned to each MET registered for service. This is a METlevel characteristic set once for the MET regardless of how manyservices, etc. the MET has. The MET ID is used by the NOC to identifyMETs. It does not have to be used within CMIS as a key field. MET IDcannot be updated once it has been assigned. A MET that requires a newMET ID for any reason would have to go through the registration processanew.

MET Signaling Code

Definition: Dialed digits from MET that identifies VN selection.Signaling codes would be assigned when a MET has multiple VirtualNetwork memberships. After the MET user enters the destination phonenumber, the pound key is hit and then the signaling code is entered ifthe caller wants to associated the outbound call with a particularvirtual network. When no signaling code is entered, implies default VNbe associated with the call.

Pending NVRAM Init Flag

Definition: Instructs the GC to download/initialize parameters for aMET.

Pending PVT Flag

Definition: This flag indicates that a PVT is required following nextMET access. If CMIS requests a PVT to help diagnose customer troubles,an update would be sent to NOC with the Flag set to Perform PVT afterNext MET access (1).

Picsel

Definition: Flag indicating if user has asked for a preferred IXCcarrier. Carrier name is contained in CARRIER field.

Record Type

Definition: Type of record defined by object. Part of the Update ResultsRecord.

Remote

Definition: Remote user--not required by the switch for MSATApplication.

Recent Configuration Event

Definition: This is a serial list of events received from the NOC thatpertain to configuration database changes.

Referential Integrity

Definition: Database "key field" relationships that bind record withinthe databases, and create dependencies for additions and deletions oftable instances.

RF Pin

Definition: Remote feature personal identification number. A user isprompted for a pin when attempting to use a remote feature.

Roam

Definition: Roam Capable--not required by the switch for MSATApplication.

RTIN

Definition: Reverse Terminal Identification Number which is also thesatellite electronic serial number on satellite only and dual modecellular/satellite METs. This is a unique identifier assigned bymanufacturer for each piece of equipment. Within CGS processing the RTINis used by the GC to signal the MET.

Satellite Id

Definition: Satellite Id of current L-band beam. The NOC populates thisfield based on MET commissioning. CMIS does not ever create or updatethis field.

SCM

Definition: Station Class Mark.

Secure Disable Flat

Definition: Channel Unit security check flag. Setting this flag tobypass security would disable ASK verification during call processingfor a MET. CMIS cannot change this flag.

Signaling Priority

Definition: Number of MET signaling requests to the GC during networkcongestion. Assigned at the MET level--each MET may have only onesignaling priority regardless of the number of VN memberships it has.The highest priority level is 0 and the lowest is seven.

TDM Change Enable Flat

Definition: Restriction on MET from changing TDM (TDM is the GSI)

Telephone Number

Definition: Phone number associated with a call type (voice, data, fax,avd) in a given virtual network.

Template

Definition: An initial set of default attribute values for each resourcebeing added.

To MET Call Barring Flags

Definition: Describes actions available to a user receiving a call attheir MET.

Trunk Access Priority

Definition: Satellite trunk queuing priority used during networkcongestion. Determines access to channels.

Virtual Network Id

Definition: Identifies the Virtual Network that the service and featureprofiles relate to. Within a single VN a MET may have one voice, data,fax and/or avd service type. Features and restrictions for thoseservices are defined on the basis of the METs membership in that VN. Ifthe MET required an additional instance of a service that it alreadysubscribed to, (e.g. a second voice number), a second virtual networkassignment would be required. Features and restrictions for that secondmembership can be defined with no relation to the existing VNmembership, but all elements that relate to the MET level cannot changewithout a ripple effect to the other services.

VMS Instance Type

Definition: Part of the Event Message

Vocoder Id

Definition: Vocoder version currently installed in the MET. CMIS willonly have the MET Class ID that a particular METs equipment maps to.NE/SE originates this and other data that describes the MET Class andsends it to the NOC.

Working Configuration

Definition: The set of resources currently being modified by theengineer. This may be an existing, complete configuration which theengineer is modifying, or may be a new, partial (or initially empty)configuration.

                                      TABLE A                                     __________________________________________________________________________    Field                                                                         No.                                                                              Field Name      Description                                                __________________________________________________________________________    1  RECORD CODE     This is the type of Call Entry (#F7)                       2  ENTRY CODE      This field tells whether the call is local or toll.                           The value in this                                                             field is determined by the TELCO through the datafill                         of Table                                                                      TOLLENTC. The DMS-MTX indexes this table based upon                           the                                                                           CHARGE CLASS assigned to the call and obtains the                             associated                                                                    ENTRY CODE. More information can be found in NTP                              411-2131-451, section 029. The following CHARGE                               CLASSES                                                                       are used:                                                                     • Load Mobile call - MOBL                                               • Direct dialed Mobile call (1+) - MOB1                                 • Operator Assisted Mobile call (0+) MOB0                               • Local Land Origination - LLOR                      3  OFEATCD         This is the originating feature code. It records                              whether or not                                                                each feature type has occurred during the call. This                          field is Y or                                                                 N or each character in the field. Y indicates that the                        feature                                                                       assigned to that location occurred during the call. N                         indicates that                                                                the feature did not occur. The feature designated                             positions are                                                                 displayed in the following order.                                             • Call Forwarding Instigation                                           • Call Forwarding Activation                                            • Call Forwarding Deactivation                                          • Call Forwarding Busy Instigation                                      • Call Forwarding Busy Activation                                       • Call Forwarding Busy Deactivation                                     • Call Forwarding No Answer Instigation                                 • Call Forwarding No Answer Activation                                  • Call Forwarding No Answer Deactivation                                • Three Way Calling                                                     • Call Transfer                                                         • Call Waiting                                                          • Vertical Feature Flag                                                 • Directed Inward Mobile Access                                         • Hotline                                                               • Intersystem Handoff                                                   • Call Delivery                                                         • Automatic Roaming                                                     • Follow Me Roaming                                                     • Call Delivery Activatable                                             • Surveillance                                                          • RF PIN Verification                                                   • RF PIN Change Features                             4  TFEATCD         Terminating feature code. It records whether or not                           each feature                                                                  type has occurred during the call. This field is Y or                         N for each                                                                    character in the field. Y indicates that the feature                          assigned to that                                                              location occurred during the call, N indicates that                           the feature did                                                               not occur. The feature designated positions are                               displayed in the                                                              following order:                                                              • Call Forwarding Instigation                                           • Call Forwarding Activation                                            • Call Forwarding Deactivation                                          • Call Forwarding Busy Instigation                                      • Call Forwarding Busy Activation                                       • Call Forwarding Busy Deactivation                                     • Call Forwarding No Answer Instigation                                 • Call Forwarding No Answer Activation                                  • Call Forwarding No Answer Deactivation                                • Three Way Calling                                                     • Call Transfer                                                         • Call Waiting                                                          • Vertical Feature Flag                                                 • Directed Inward Mobile Access                                         • Hotline                                                               • Intersystem Handoff                                                   • Call Delivery                                                         • Automatic Roaming                                                     • Follow Me Roaming                                                     • Call Delivery Activatable                                             • Surveillance                                                          • RF PIN Verification                                                   • RF PIN Change Features                             5  CALLING NUMBER  This field is the calling party's number. It contains                         a Mobile                                                                      Identification Number (MIN) for cellular originated                           calls. When                                                                   the mobile is registered roamer, this field contains                          the assigned                                                                  directory number rather than the MIN.                      6  FILLER                                                                     7  CALLING SYSTEM ID                                                                             This field is the calling party system identification.                        If Split Ticket                                                               Billing is activated for the originator, the calling                          system ID in the                                                              new CDR is set to the system ID of the MSA that the                           mobile is in                                                                  when the new record is started.                                               Note: With the current version of CIS-3, this field                           can only be                                                                   filled for subscribers and permanent roamers.              8  ORIGINATING MSA This field is the initial calling party MSA, if it is                         a cellular                                                                    originated call. Otherwise, it is filled with the                             background                                                                    character.                                                 9  ORIGINATING ROAMER                                                                            This field is the roamer or home status of the calling                        party, if it is                                               INDICATOR       a mobile originated call. Otherwise, it is filled with                        the                                                                           background character. If the field equals 0, the                              mobile is a                                                                   permanent subscriber. If the field value is 1, then                           the subscriber is                                                             either a temporary or a mobile denied service. When                           the value is                                                                  2, then the mobile is a permanent roamer. When the                            value is 3 the                                                                mobile is a network roamer.                                10 ORIGINATING STATION CLASS                                                                     This field is the station classmark as transmitted by                         the originating                                               MARK            mobile. This field consists of the Power Class (1-8)                          followed by                                                                   Y or N for Expanded Spectrum and Y or N for                                   Discontinuous                                                                 Transmission.                                                                 Note: This field consists of three blanks if the                              originator is not a                                                           mobile.                                                    11 FILLER                                                                     12 ORIGINATING CHANNEL TYPE                                                                      This field is the channel type capability as                                  transmitted by the                                            CAPABILITY      originating mobile. This field is Y or N for each                             character is the                                                              field. Y indicates that this channel type is                                  available, N indicates                                                        that this channel type is not applicable. The channel                         type                                                                          designated positions are:                                                     • Other voice coding                                                    • Other DQPSK channels                                                  • Digital half rate channels                                            • Digital full rate channels                                            • Analog channels                                                       Note: This field will consists of 5 blanks if the                             originator is not a                                                           mobile.                                                    13 ORIGINATING CHANNELS                                                                          This field consists of the channels used the                                  terminating mobile                                            USED            during a call. This field is Y or N for each character                        in the field.                                                                 Y indicates that this channel type is used, N                                 indicates that this                                                           channel type is not applicable. The channel type                              designated                                                                    positions are:                                                                • Other voice coding                                                    • Other DQPSK channels                                                  • Digital half rate channels                                            • Digital full rate channels                                            • Analog channels                                                       Note: This field will consists of 5 blanks if the                             originator is not a                                                           mobile.                                                    14 CALLING SERIAL NO                                                                             This field consists of the 2 subfields: manufacturer's                        code and                                                                      serial number. The manufacturer's code range is 0 to                          255. The                                                                      calling party mobile unit serial number field is only                         filled if the                                                                 S-bit is set to ON. The valid range of this field is 0                        to 16777215.                                               15 FILLER                                                                     16 CREDCARD        This field is the credit card number used by the                              mobile.                                                    17 DIALED NUMBER   This field is the number dialed by the originator                             mobile. It is                                                                 captured with the exact digits dialed. It contains a                          speed number,                                                                 MIN or NPA-NXX-XXXX number. The range of this field is                        a                                                                             valid number of up to 32 digits (for international                            calls).                                                    18 CALLED NUMBER   This field is the called party's number from the                              mobile. It                                                                    displays the outpulsed digits for terminated calls.                           and the EA                                                                    prefix (10XXX) of an EA call. If the called party is a                        roamer, it                                                                    contains a MIN and the DIALED NUMBER field contains                           its                                                                           temporary NPA-NXX-XXXX number. If wire terminated, it                         contains an NPA-NXX-XXXX number. The range of this                            field is                                                                      a valid number of up to 24 digits (for international                          calls).                                                                       NOTE: although the DIALED NUMBER is always                                    translated,                                                                   fields 10 to 11 can contain the same information. the                         prefix                                                                        10XXX in EA calls will be shown regardless whether the                        prefix                                                                        was dialed or not in addition to showing the outpulsed                        number to                                                                     the Access Tandem or the IC. The XXX indicates the                            chosen                                                                        carrier.                                                   19 CALLED SYSTEM ID                                                                              This filed is called party system identification. When                        Split Ticket                                                                  Billing is activated for the terminator, the calling                          system ID in the                                                              new CDR is set to the system ID for the MSA that the                          terminator                                                                    is in when the new CDR is started.                                            NOTE: with the current version of CIS-3, this field                           can only be                                                                   filled for subscribers and permanent roamers.              20 TERMINATING MSA This field is the initial called party MSA, if it is                          cellular                                                                      terminated call. Otherwise, it is filled with the                             background                                                                    character.                                                 21 TERMINATING ROAMER                                                                            This field is the roam or home status of the called                           party, it is a                                                INDICATOR       mobile terminated call. Otherwise, it is filled with                          the                                                                           background character.                                      22 TERMINATING STATION                                                                           This field is the station classmark transmitted by the                        terminating                                                   CLASS MARK      mobile. This field consists of the Power Class (1-8)                          followed by Y                                                                 or N for Expanded Spectrum and Y or N for                                     Discontinuous                                                                 Transmission.                                                                 NOTE: This field consists of three blanks if the                              originator is not a                                                           mobile.                                                    23 FILLER                                                                     24 TERMINATING CHANNEL                                                                           This field is the channel type capability as                                  transmitted by the                                            TYPE CAPABILITY terminating mobile. This field is Y or N for each                             character is the                                                              field. Y indicates that this channel type is                                  available, N indicates                                                        that this channel type is not applicable. The channel                         type                                                                          designated positions are:                                                     • Other voice coding                                                    • Other DQPSK channels                                                  • Digital half rate channels                                            • Digital full rate channels                                            • Analog channels                                                       Note: This field will consists of 5 blanks if the                             originator is not a                                                           mobile.                                                    25 TERMINATING CHANNELS                                                                          This field consists of the channels used the                                  terminating mobile                                            USED            during a call. This field is Y or N for each character                        is the field. Y                                                               indicates that this channel type is used, N indicates                         that this channel                                                             type is not applicable. The channel type designated                           positions are:                                                                • Other voice coding                                                    • Other DQPSK channels                                                  • Digital half rate channels                                            • Digital full rate channels                                            • Analog channels                                                       Note: This field will consists of 5 blanks if the                             originator is not a                                                           mobile.                                                    26 CALLED SERIAL NO                                                                              This field is the called party mobile unit serial                             number. The field is                                                          only filled if the S-bit is set to ON.                     27 CALL TYPE       This field is the type of call made. It is determined                         by the type of                                                                trunks on each side of the call. The valid call types                         are:                                                                          • Mobile-to-Mobile - 0                                                  • Mobile-to-Land - 1                                                    • Mobile-to-Operator - 2                                                • Land-to-Mobile - 3                                                    • Land-to-Land - 4                                                      • Operator-to-Mobile - 6                             28 BILLING NUMBER  This field is the number of the billed party. It                              always contains a                                                             MIN. The billing party fields are pertinent only to                           Vertical                                                                      Services.                                                  29 FILLER                                                                     30 ACCNTCOD        This field is the account code number dialed by the                           originator.                                                31 FILLER                                                                     32 AUTHCODE        This field contains the authorization code entered by                         the subscriber.                                                               It will contain a system wide authorization code if                           one was entered                                                               or a station specific one if it was entered and the                           subscriber has                                                                station specific authorization code recording on,                             field AUTHREC                                                                 in Table CELLFEAT for the MAC feature. If no                                  authorization                                                                 code is entered, this field will be blank.                 33 FILLER                                                                     34 TREATMENT CODE  This field is the treatment given a call before it is                         answered.                                                                     Treatments provided by the DMS-MTX are listed below                           along with                                                                    the conditions which cause them to be routed.                                 UNDT (00):                                                                    UNDEFINED TREATMENT - This field is the default value                         for                                                                           entries in Class of Service Screening and Prefix                              Treatment tables                                                              when no treatment is required. The operating company                          does not                                                                      supply any input data.                                                        NOSC (01):                                                                    NO SERVICE CIRCUIT - NOSC is applied when a DIMA                              facility                                                                      cannot attach a DT receiver to the call. This                                 condition occurs                                                              when:                                                                         1) a request for a DT receiver is queued but a wait                           timeout occurs                                                                before a DT receiver becomes available                                        2) the DT receiver wait queue is full.                                        PDIL (02):                                                                    PARTIAL DIAL TIMEOUT - PDIL occurs in the following                           instances:                                                                    1) An insufficient number of digits have been received                        for a call                                                                    2)No ST pulse is received on a MF trunk,                                      3)An invalid digit is collected.                                              PSIG (03):                                                                    PERMANENT SIGNAL TIMEOUT - This field is the treatment                        to                                                                            which a trunk is routed when origination occurs on an                         incoming or                                                                   two-way trunk, but no digits are dialed within the                            period of time                                                                specified by the trunk group parameter PSPDSEIZ.                              VACT (06):                                                                    VACANT CODE TREATMENT - An unassigned NPA code,                               office code, or country code is dialed.                                       MSCA (07):                                                                    MISDIRECTED CAMA CALL - This field is the treatment                           which a mobile is routed when making local calls which                        attempt to                                                                    switch via the toll network but are not permitted, or                         when the prefix                                                               digits 0 or 1 is dialed in error on a local call.                             MSLC (08):                                                                    MISDIRECTED LOCAL CALL - This field is the treatment                          given                                                                         in the following cases:                                                       1) For a mobile originating an operator assisted call                         (0+) to 800 or                                                                555 codes.                                                                    2) When prefix digit 0 or 1 is not dialed on a toll                           call and the prefix                                                           treatment table specifies a mandatory prefix digits on                        toll calls.                                                                   NBLH (09):                                                                    NETWORK BLOCKED HEAVY TRAFFIC - This field is the                             treatment given when the intermediate cause of failure                        is the inability                                                              to get a path through the network.                                            NBLN (10):                                                                    NETWORK BLOCKING NORMAL TRAFFIC - This field is the                           treatment given when a call is a aborted due to                               blocking (failure to                                                          get a channel) in the terminating peripheral module.                          HNPI (16):                                                                    HOME NPA INTERCEPT - This field is the treatment to                           which a                                                                       mobile or trunk is routed upon dialing home NPA when                          home NPA                                                                      dialing is not permitted.                                                     BLDN (18):                                                                    BLANK DIRECTORY NUMBER - This field is the treatment                          given for unassigned directory numbers.                                       BUSY (19):                                                                    BUSY LINE This field is the treatment given in either                         of the                                                                        cases:                                                                        1)A mobile dials its own directory number                                     2)A mobile or trunk dials a directory number that is                          busy.                                                                         TDND:                                                                         TOLL DENIED - This field is the treatment to which a                          mobile is                                                                     routed when a toll call is attempted by a subscriber                          who is denied                                                                 toll access.                                                                  RODR (25):                                                                    REORDER - RODR is given in either of the following                            conditions:                                                                   1)More than the maximum number of digits required for                         a call is                                                                     outpulsed by an incoming trunk.                                               2)An unexpected error condition occurs on an outgoing                         trunk while                                                                   a call is up. An example of this would be either                              network integrity                                                             loss, invalid A&B bit state received, or force release                        is ordered                                                                    from MAP position for a terminating circuit.                                  ORSS (27):                                                                    ORIGINATING SERVICE SUSPENSION - This is the                                  treatment                                                                     to which a temporarily - invalid mobile is routed upon                        originating a                                                                 call.                                                                         TESS (28):                                                                    TERMINATING SERVICE SUSPENSION - This is the                                  treatment                                                                     to which a call is routed when the terminating mobile                         is temporarily                                                                invalid.                                                                      DNTR (33):                                                                    DENIED TERMINATION - his treatment is applied when the                        10                                                                            over-dialed digits correspond to a Permanent Roamer or                        Normal                                                                        Subscriber with the DTM (denied Termination) option.                          GNCT (58):                                                                    GENERALIZED NO CIRCUIT - This is the treatment to                             which a                                                                       call is routed when no DOD trunk is available for                             mobile.sub.-- to.sub.--l land                                                 calls.                                                                        ANTO (66):                                                                    ANSWER TIMEOUT - This is the treatment to which the                           originator is routed when a ringing mobile does not                           answer within                                                                 the ringing timeout value.                                                    FNAL(68):                                                                     FEATURE NOT ALLOWED - An attempt to access a vertical                         feature that is not allocated in Table Cellular to the                        Mobile ID                                                                     number, or an attempt has been made to access two                             different                                                                     vertical features that cannot coexist from the same                           control mobile.                                                               UMOB (69):                                                                    UNREGISTERED MOBILE - This is the treatment to which                          a                                                                             mobile attempting origination is routed when its MIN                          does not                                                                      verify.                                                                       PGTO (86):                                                                    MOBILE PAGE TIME OUT - This is the treatment to which                         an                                                                            originator is routed when the terminating mobile fails                        to respond to                                                                 a page request.                                            35 FILLER                                                                     36 BILLING SERIAL NO                                                                             This is the billing party mobile unit serial number.                          This field is                                                                 only filled if the S-bit is set ON. Valid range is 0                          to 16777215.                                               37 EVENT INFO DIGIT                                                                              The following information is provided on a per call                           event basis:                                                                  • Y Y N N Y Y N N N - Answer                                            • Y N Y N Y N Y N Y - Calling Party Disconnect                          • N Y N Y N Y N Y N - Called Party Disconnect                           • N N N N Y Y Y Y N - Blue Box Fraud                                    • N N N N N N N N Y - Blocked                        38 ORIGINATING INTERSYSTEM                                                                       This is the originating intersystem billing ID. This                          ID is used to                                                 BILLING ID      associate CDRs for intersystem calls on various                               switches. The first                                                           5 digits are the switch ID, the next three digits are                         the switch                                                                    number, and the final eleven digits are an ID number                          intended to                                                                   make the entire billing ID unique.                         39 FILLER                                                                     40 TERMINATING INTERSYSTEM                                                                       This is the terminating intersystem billing ID. This                          ID is used to                                                 BILLING ID      associate CDRs for intersystem calls on various                               switches. The first                                                           five digits are the switch ID, the next three digits                          are the switch                                                                number, and the final eleven digits are an ID number                          intended to                                                                   make the entire billing ID unique.                         41 FILLER                                                                     42 FIRST ORIGINATING CLLI                                                                        This is the CLLI for the voice trunk that the call                            began on. All                                                                 eight fields which indicate the trunks and their                              members are                                                                   updated during the call. It is not changed when Split                         Ticket Billing                                                                is activated.                                              43 FIRST ORIGINATING MEMBER                                                                      This field is the trunk member number for the voice                           trunk that the                                                                call began on. It is not changed when Split Ticket                            Billing is                                                                    activated.                                                 44 PREVIOUS ORIGINATING CLLI                                                                     This field is the CLLI for the voice trunk that the                           originator was on                                                             before the last handoff was activated and the CDR was                         reported.                                                                     IF there are no handoffs on the originating side of                           the call, the                                                                 background character is filled. It is not affected by                         Split Ticket                                                                  Billing.                                                   45 PREVIOUS ORIGINATING                                                                          This field is the trunk member number far the voice                           trunk that the                                                MEMBER          originator was on before the last handoff was                                 activated and the                                                             CDR was reported. It is not affected by Split Ticket                          Billing. If                                                                   there are no handoffs and the originating side of the                         call, the                                                                     background character is filled.                            46 LAST ORIGINATING CLLI                                                                         This field is the CLLI for the voice trunk that the                           originator was on                                                             when the CDR was reported. It is not affected by Split                        Ticket                                                                        Billing.                                                   47 LAST ORIGINATING MEMBER                                                                       This field is the trunk member number for the voice                           trunk that the                                                                originator was on when the CDR was reported. It is not                        affected                                                                      by Split Ticket Billing.                                   48 ORIGINATING TIME                                                                              For the billing entry of a cellular originator, this                          is the day of the                                                             year and time (hour, minute, second) that a voice                             channel is                                                                    allocated for the billing entry of a cellular                                 terminated call, this is                                                      the day of the year and the time that the terminating                         trunk is                                                                      seized.                                                    49 HANDOFFS        This field is the number of handoffs made during the                          call. This                                                                    count begins at 1 and continues to 255. Upon reaching                         255 it does                                                                   not wrap around to 0.                                      50 FIRST TERMINATING MEMBER                                                                      This field is the CLLI for the voice trunk that the                           terminator was                                                                on when the call was answered. Not affected by Split                          Ticket                                                                        Billing.                                                   51 FIRST TERMINATING MEMBER                                                                      This field is the trunk member number for the voice                           trunk that the                                                                terminator was on when the call was answered. Not                             affected by                                                                   Split Ticket Billing.                                      52 PREVIOUS TERMINATING CLLI                                                                     This field is the CLLI for the voice trunk that the                           terminator was                                                                on before the last handoff was activated and the CDR                          was                                                                           if there are no handoffs on the terminating side of                           the                                                                           call, the background character is filled. Not affected                        by Split                                                                      Ticket Billing (STB).                                      53 PREVIOUS TERMINATING                                                                          This field is the trunk member for the voice trunk                            that the                                                      MEMBER          terminator was on before the last handoff was                                 activated and the                                                             CDR was reported. If there are no handoffs on the                             terminating                                                                   side of the call, the background character is filled.                         Not affected by                                                               Split Ticket Billing.                                      54 LAST TERMINATING CLLI                                                                         This field is the CLLI for the voice trunk that the                           terminator was                                                                on the CDR was reported. Not affected by Split Ticket                         Billing.                                                   55 LAST TERMINATING MEMBER                                                                       This field is the trunk member number for the voice                           trunk that the                                                                terminator was on when the CDR was reported. Not                              affected by                                                                   Split Ticket Billing.                                      56 DISCONNECT TIME This field is the day of the year and time that a                             on-hook is detected                                                           on either end of the call.                                 57 SERVING TRANSLATION                                                                           This field is the number of the translation scheme                            applied to the                                                SCHEME          dialed number.                                             58 CALL DURATION   This is the connection duration of the call in                                seconds. For a                                                                normally completed call (completion code 00), this is                         the time                                                                      duration between off-hook detection on the terminating                        mobile or                                                                     line and on-hook at either end of the call                                    (conversation time).                                                          Upon reaching 999999, it does not wrap around to                              zero.                                                      59 INFO DIGITS     The following events are observed during the call:                            information is provided on a per call event basis:                            • 1 N Y N Y N Y N Y Service Observed ?                                  • 1 N N Y Y N N Y Y Charge ?                                            • 1 N N N N Y Y Y Y Traffic Sampled ?                                   • 2 N Y N Y N Y N Y ANI fail?                                           • 2 N N Y Y N N Y Y Operator Dialed ?                                   • 2 N N N N Y Y Y Y Operator Identified?                                NOTE: This field is not yet implented.                     60 ORIG HOLD       This is the total amount of time, in seconds, on hold                         by the                                                                        originator.                                                61 IX (CARRIER)    This is the equal access toll carrier.                     62 TERM HOLD       This is the total amount of time, in seconds, on hold                         by the                                                                        terminator.                                                63 COMPLETION CODE This the manner in which a call is terminated.                                NOTE: Completion code values other than 00 indicate                           abnormal                                                                      call completions. For value 4 (RF Signal Lost), the                           call duration                                                                 indicates the time span between answer and signal lost                        detection by                                                                  the DMS-MTX. Values 5 and 6 indicate billable calls,                          but the call                                                                  duration field can not indicate the full conversation                         time. For these                                                               codes, the call duration can be calculated as the                             difference between                                                            the disconnect and the origination times.                                     Code                                                                             Meaning                                                                    00 NORMAL CALL The call is completed after a on-hoot                             is                                                                            detected at either side of the call.                                       01 TREATMENT SET - The call is not completed as                                  intended                                                                      by the calling party. Instead it is routed to a                               treatment. The                                                                exact treatment set can be determined from the                                TREATMENT CODE.                                                            02 CALL ABANDON - An on-hook by the originating party                            is                                                                            detected before the call is completely routed.                             03 ABNORMAL CALL - This field is the default                                     completion                                                                    code given to an abnormally completed call. This                              results                                                                       only if the cause of the termination is                                       specifically                                                                  determined.                                                                04 RF SIGNAL LOST - A mobile unit failure message is                             received from a (CSC) while call processing is                                waiting for                                                                   SAT.                                                                       05 MOBILE UNIT FAILURE - A mobile unit failure                                   message                                                                       is received from a CSC while call processing is in                            any state                                                                     other than waiting for SAT. Note: The RF SIGNAL                               LOST                                                                          is a special case of a mobile unit failure.                                06 CELL SITE FAILURE - AS cell site failure message                              is                                                                            received from a CSC.                                                       10 HANDOFF OCCURRED - The CDR record was split due                               to a handoff.                                           64 OEXTSYS         This is the amount of time the originator is not in                           the first reporting                                                           system.                                                    65 ANSWER TYPE     This field displays the manner in which a call is                             answered. The                                                                 following answer types are valid:                                             Code                                                                             Meaning                                                                    01 ANSWER DETECT NO VOICE - The ATD has detected                                 an answer, but an identifiable signal has not been                            present for                                                                   72 seconds or longer.                                                      02 ANSWER DETECT VOICE - The ATD has detected a                                  pattern of signals not classifiable as call                                   progress tones.                                         65 ANSWER TYPE     Code                                                                             Meaning                                                    (CONTINUE)      03 RING BACK SOFTWARE DETECT - The ATD has                                       counted the default number of audible rings.                               04 HARDWARE ANSWER - The conventional off-hook                                   signal has been detected on a line or trunk.                               05 ATD HIGH DRY TIMEOUT - The ATD has not detected a                             constant tone of 60 ms within the default timeout                             limit.                                                                     07 ATD NO CMS BIT TRANSITION - The end-of-outpulsing                             has not been detected within a 20-second wait                                 period.                                                                    08 BUSY SOFTWARE DETECT - The ATD has counted 4                                  signals identified as a busy call process tone.                            09 REORDER SOFTWARE DETECT - The ATD has counted                                 eight signals identified as a reorder call progress                           tone.                                                   66 TEXTSYS         This field is the amount of time the terminator is not                        in the first                                                                  system.                                                    67 SPARE                                                                      __________________________________________________________________________

    ______________________________________                                        GLOSSARY                                                                      ______________________________________                                        A       Availability                                                          AAC     Airline Administrative Communications                                 AARM    Access Authentication Request                                         ABH     Average Busy Hour                                                     AC      Alternating Current                                                   ACU     Access Channel Unit                                                   ACU     Antenna Control Unit                                                  AD      Attribute Dictionary                                                  AEDC    After Effective Date of Contract                                      AFC     Automatic Frequency Control                                           AFS     Antenna/Front-end Subsystem                                           AGC     Automatic Gain Control                                                AIOD    Automatic Number Identification Outward Dialing                       AMI     Alternative Mark Inversion                                            AMPS    North American Analog and Digital Cellular                                    Networks                                                              AMSC    American Mobile Satellite Corporation                                 AMS(R)S Aeronautical Mobile Satellite (Route) Service                         AMSS(R) Aeronautical Mobile Satellite Services (Reserved)                     ANI     Automatic Number Identification                                       ANSI    American National Standards Institute                                 ANT     Antenna                                                               AOC     Aircraft Operational Communications                                   APC     Airline Passenger Communications                                      API     Applications Program Interface                                        AR      Automatic Roaming                                                     ARC     Atlantic Research Corporation                                         ASK     Access Security Key                                                   ASN.1   Abstract Syntax Notation One                                          AT      Command set for a DTE to communicate with                                     asynchronous host                                                     ATC     Air Traffic Control                                                   AVD     Alternate Voice/Data Calls                                            AWGN    Additive White Gaussian Noise                                         AZ      Azimuth                                                               B8ZS    Bipolar with 8 Zeros Substitution                                     BB      Bulletin Board                                                        BBS     Bulletin Board Service                                                BER     Bit Error Rate                                                        BERT    Bit Error Rate Tester                                                 BID     Beam Identifier Code                                                  BIT     Built In Test                                                         BITE    Built-In Test Equipment                                               BPS     Bits Per Second                                                       BS      Base Station                                                          BSPU    Baseband Signaling Processing Unit                                    BSS     Base Station Switch                                                   C/No    Carrier to Noise Power Density Ratio                                  CAC     Channel Access and Control                                            CAF     Call Failure Message                                                  CCCS    Command, Control, and Communications Subsystem                        CCIR    Consultative Committee International de Radio                         CCITT   Consultative Committee International Telegraph and                            Telephone                                                             CCU     Communications Channel Unit                                           CD      Call Delivery                                                         CDR     Call Detail Record                                                    CDR     Critical Design Review                                                CDRL    Contract Data Requirements List                                       CE      Common Equipment                                                      CG      Control Group                                                         CGID    Control Group Identification Number                                   CGS     Communications Ground Segment                                         CHA     Channel Assignment Message                                            CHREL   Channel Release Message                                               CHREQ   Channel Request Message                                               CI      Configuration Item                                                    CIBER   Cellular Intercarrier Billing Exchange Roamer                         CIC     Carrier Identification Code                                           CM      Configuration Management                                              CMIP    Common Management Information System                                  CMIS    Configuration Management Information System                           CMIS    Customer Management Information System                                COTS    Commercial off-the-Shelf                                              CP      Circuit Pool                                                          CPD     Call Processing Demonstration                                         CPS     Circuit Pool Segment                                                  CPU     Central Processing Unit                                               C/PV    Commissioning/Performance Verification                                CRC     Cyclic Redundancy Check                                               CS      Communications System                                                 CSC     Computer Software Component                                           CSCI    Computer Software Configuration Item                                  CSDT    Channel Switchover Detection Time                                     CSF     Critical System Functionality                                         CSMA/CD Carrier Sense Multiple Access with Collision                                  Detection                                                             CSMP    Circuit Switch Management Processor                                   CSMPCS  Circuit Switch Management Data Processor Equipment                            Communications System                                                 CSPU    Channel Signal Processing Unit                                        CSR     CAC Statistics Request                                                CSREP   Call Status Reply Message                                             CSREQ   Call Status Request Message                                           CSU     Computer Software Unit                                                CSUG    Computer Software Unit Group                                          CTB     Customer Test Bed                                                     CTN     Cellular Telephone Network                                            CTN     Cellular Terrestrial Network                                          CTNI    Cellular Telephone Network Interface                                  CU      Channel Unit                                                          CUD     Call User Data                                                        CUG     Closed User Group                                                     CUP     Channel Unit Pool                                                     CUS     Channel Unit Subsystem                                                CVR     Cellular Visitor Registration                                         CVRACK  Cellular Visitor Registration Acknowledge                             CW      Carrier Wave                                                          CWCHA   Call Waiting Channel Assignment Message                               DAMA    Demand Assignment Multiple Access                                     db      Database                                                              dbc     Decibel Relative to Carrier                                           dB      decibels                                                              dBi     dB Relative to Isotropic                                              dBm     dB relative to 1 milli watt                                           dBW     decibels relative to 1 watt                                           D bit   `Data Configuration` bit in X.25                                      DBMS    DataBase Management System                                            dBw     dB Relative to 1 Watt                                                 DC      Direct Current                                                        DCE     Data Circuit Terminating Equipment                                    DCE     Data Communications Equipment                                         DCL     Digital Command Language                                              DCN     Down CoNverter                                                        DCR#    Document Control Release #                                            DCU     Data Channel Unit                                                     DD      Design Document                                                       DDCMP   Digital Data Communications Message Protocol                          DDS     Direct Digital Synthesis                                              DEC     Digital Equipment Corporation                                         DECmcc  Digital's Network Management System                                   DEQPSK  Differential Encoded Quadrature Phase Shift Keying                    DET     Data Equipment Terminal                                               DFD     Data Flow Diagram                                                     DH      Data Hub                                                              DH-D    Outbound Time Division Multiplex Channel from Data                            Hub to Mobile Terminal                                                DHP     Data Hub Processor                                                    DHSI    DH-D Selector Identification Code                                     DID     Direct Inward Dialing                                                 D1Ds    Data Item Descriptions                                                DME     Dial-Up Modem Emulation                                               DMQ     DEC Message Queue                                                     DMS     Digital Multiplex System                                              DN      Directory Number                                                      DNS     Digital Name Service                                                  DOC     Canadian Department of Communications                                 DOD     Direct Outward Dialing                                                DPSK    Differential Phase Shift Keying                                       DQPSK   Differentially Encoded Quadrature Phase Shift                                 Keying                                                                DSO     Digital Service Level Zero (single 64K b/s                                    channel)                                                              DS 1    Digital Service Level One (twenty four voice                                  channels)                                                             DSP     Digital Signal Processing                                             DSSS 1  Digital Subscriber Signaling System 1                                 DTC     Digital Trunk Controller                                              DTE     Data Terminal Equipment                                               DTE     Data Terminal Element                                                 DTMF    Dual Tone Multiple Frequency                                          DVSI    Digital Voice Systems, Inc.                                           Eb/No   Bit Energy to Noise Power Density Ratio                               ECN     Engineering Change Notice                                             EFD     EF Data, Inc.                                                         EFTIN   Encrypted Forward Terminal Identification Number                      E-I     Exchange - Interexchange                                              EIA     Electronic Industries Association                                     EICD    Element Interface Control Document                                    EIE     External Interface Equipment                                          EIRP    Equivalent Isotropic Radiated Power                                   E1      Elevation                                                             EMC     ElectroMagnetic Compatibility                                         EMI     ElectroMagnetic Interference                                          eng     engineer or engineering                                               EO      End Office                                                            EO      External Organizations                                                EOD     End of Data                                                           ESN     Electronic Serial Number                                              FAX     Facsimile                                                             FCA     Functional Configuration Audit                                        FCC     Federal Communications Commission                                     FCS     Fading Channel Simulator                                              FDMA    Frequency Division Multiple Access                                    FEC     Forward Error Correction                                              FES     Feederlink Earth Station                                              FES-C   Inbound Communication channel from Feederlink                                 Earth Station to Mobile Terminal                                      FES-I   Interstation signaling channel from Feederlink                                Earth Station to Group Controller                                     FES/MT  Feederlink Earth Station/Mobile Terminal                              FES-RE  Feederlink Earth Station-Radio Frequency Equipment                    FES-TE  Feederlink Earth Station Terminal Equipment                           FFT     Fast Fourier Transform                                                FIS     Feederlink Earth Station Interface Simulator                          FIT     Fault Isolation Tests                                                 FIU     Fax Interface Unit                                                    FMT     Fixed Mobile Terminal                                                 FMA     Field Programmable Gate Array                                         FPMH    Failures per Million Hours                                            FRO     Frequency Reference Oscillator                                        FT      Fault Tolerant                                                        FTE     Fax Terminal Equipment                                                FTIN    Forward Terminal Identification Number                                G/T     Gain to System Noise Ratio                                            GBF     Gateway/Base Function                                                 GBS     Gateway Base System                                                   GC      Group Controller                                                      GC-I    Interstation signaling channel from Group                                     Controller to Feederlink Earth Station                                GC-S    Time Division Multiplex Signaling channel from                                Group Controller to Mobile Terminal                                   GCSST   GC-S Search Time                                                      GEN     Generator                                                             GHz     Giga (1,000,000,000) Hertz (cycles per second)                        GMACS   Graphical Monitor And Control System                                  GPIB    General Purpose Instrument Bus                                        GPS     Global Positioning System                                             GS      Gateway Station                                                       GSI     GC-S Selector Identifier                                              GW      Gateway                                                               GWS     Gateway Switch                                                        GWS/BSS Gateway Switch/Base Station Switch                                    H/W     Hardware                                                              HCHREQ  Handoff Channel Request                                               HDP     Hardware Development Plan                                             HLR     Home Location Register                                                HMI     Human Machine Interface                                               HOT     Hand-off Test                                                         HPA     High Power Amplifier                                                  HRS     Hardware Requirements Specification                                   HWCI    Hardware Configuration Item                                           HW/SW   Hardware/Software                                                     Hz      Hertz                                                                 I       In Phase channel                                                      IAW     In Accordance With                                                    IC      Interexchange Carrier                                                 ICD     Interface Control Document                                            ICI     Instrument Control Interface                                          ICP     Intelligent Cellular Peripheral                                       ICU     Interstation Channel Unit                                             ICWG    Interface Control Working Group/Interface                                     Coordination Working Group                                            ID      Identification                                                        IEEE    Institute of Electrical and Electronics Engineers                     IF      Intermediate Frequency                                                IFIS    Intermediate Frequency Subsystem                                      IFL     Interfacility Link                                                    IF IFL  Intermediate Frequency Internal Facility Link                         IHO     Interstation Hand-Off                                                 IICD    Internal Interface Control Document                                   IICWG   Internal Interface Control Working Group                              IM      Intermodulation                                                       IMBE    Improved Multiband Excitation                                         IOC     Input/Output Controller                                               IP      Internet Protocol                                                     ISCU    Interstation Signaling Channel Unit/Interstation                              Channel Unit                                                          ISDN    Integrated Services Digital Network                                   ISL     Interstation Signaling Link                                           ISO     International Standards Organization                                  IVDCPD  Integrated Voice & Data Call Processing                                       Demonstration                                                         IVDM    Integrated Voice/Data Mobile Terminal                                 KBPS    Kilo (1,000) Bits per Second                                          kHz     Kilohertz                                                             KLNA    K-band Low Noise Amplifier                                            KP      Key Pulse                                                             LAN     Local Area Network                                                    LAP     Link Access Procedure                                                 LAPB    Link Access Procedure using a balanced mode of                                operation                                                             LATA    Local Access and Transport Area                                       LBP     Local Blocking Probability                                            LCN     Logical Channel Number                                                LLCSC   Lower Level Computer Software Component                               LLNA    L-band Lowe Noise Amplifier                                           LLS     Lower Level Specification                                             LNA     Low Noise Amplifier                                                   LOI     Level of Integration                                                  LPP     Link Peripheral Processor                                             LRU     Line Replaceable Unit                                                 LRU     Lowest Replaceable Unit                                               LSSGR   Loval Access and Transport Area Switching Systems                             Generic Requirements                                                  MAP     Maintenance Administrative Position                                   MAP     Mobile Application Part                                               M bit   `More Data` bit in X.25                                               M&C     Monitor and Control                                                   MCC     Management Control Center                                             MCGID   Mobile Data Service Control Group Identification                              Number                                                                MDLP    Mobile Data Service Data Link Protocol                                MDS     Mobile Data Service                                                   MDSR    MDLP Statistics Request                                               MEA     Failure Modes and Effects Analysis                                    MEF     Minimum Essential Functionality                                       MELCO   Mitsubishi Electronic Company                                         MET     Mobile Earth Terminal (a.k.a. MT)                                     MET-C   Communication Channel Between Mobile Terminal and                             Feederlink Earth Station                                              MET-DRd Inbound Slotted Aloha Data Channel                                    MET-DRr Inbound Slotted Aloha Reservation Channel                             MET-DT  Inbound Packet Time Division Multiple Access                                  Channel                                                               MET-SR  Random Access Signaling Channel from Mobile                                   Terminal to Group Controller                                          MET-ST  Time Division Multiple Access signaling channel                               from Mobile Terminal to Group Controller                              MF      Multiple Frequency                                                    MFID    Manufacturer Identification                                           MGSP    Mobile Terminal to Group Controller Signaling                                 Protocol                                                              MHz     Mega Hertz (cycles per second)                                        MIB     Management Information Base                                           MIR     Management Information Region                                         MIRQ    MT Initialization Request                                             MIS     Mobile Terminal Interface Simulator                                   MIS     Mobile Earth Terminal Interface Simulator                             ML      Message Layer                                                         MLCSC   Mid Level Computer Software Component                                 MLP     Multilink Procedure                                                   MMI     Man Machine Interface                                                 MMRS    Mobile Road Service                                                   MMSS    Maritime Mobile Satellite Services                                    MNMS    Mobile Data Service Network Management Subsystem                      MNP     Multi Network Protocol                                                MODEM   MODulator/DEModulator                                                 MOS     Mean Opinion Score                                                    MOV     Method of Verification                                                MPLP    Mobile Data Service Packet Layer Protocol                             MPR     MPR Teltech Inc.                                                      MRI     Minimum Request Interval                                              MRS     Mobile Radio Service                                                  MSAT    Mobile Satellite                                                      MSC     Mobile Switching Center                                               MSS     Mobile Satellite Service                                              MSSP    Mobile Terminal Specialized Services Protocol                         ms      millisecond                                                           MT      Mobile Terminal                                                       MT-C    Communication Channel Between Mobile Terminal and                             Feederlink Earth Station                                              MT-DRd  Inbound Slotted Aloha Data Channel                                    MT-DRr  Inbound Slotted Aloha Reservation Channel                             MT-DT   Inbound Packet Time Division Multiple Access                                  Channel                                                               MT ASK  Mobile Terminal Access Security Key                                   MTBF    Mean-Time Between Failures                                            MTBRA   Mean-Time Between Restoral Actions                                    MTCRS   Mobile Telephone Cellular Roaming Service                             MT-MET  Mobile Terminal to Mobile Terminal                                    MT-MT   Mobile Terminal to Mobile Terminal                                    MTP     Mobile Data Service Transaction Protocol                              MT-PSTN Mobile Terminal/Public Switched Telephone Network                     MTS     Mobile Telephone Service                                              MT-SR   Random Access Signaling Channel from Mobile                                   Terminal to Group Controller                                          MTSR    MTP Statistics Request                                                MT-ST   Time Division Multiple Access Signaling Channel                               from Mobile Terminal to Group Controller                              MTTR    Mean-Time to Repair                                                   MTX     Mobile Telephone Exchange                                             MULP    Mobile Data Service Unacknowledged Link Protocol                      MUSR    MULP Statistics Request                                               NACN    North American Cellular Network                                       NADP    North American Dialing Plan                                           NANP    North American Numbering Plan                                         NAP     Network Access Processor                                              NAP-C   Network Access Processor for the Communications                               Channel                                                               NAP-CU  Network Access Processor-Channel Unit                                 NAP-D   Network Access Processor for the Data Channel                         NAP-N   Network Access Processor for the Network Radio                                Channel                                                               NAP-S   Network Access Processor for the Signaling Channel                    NAS     Network Access Subsystem                                              NASP    National Aerospace Plan                                               NCC     Network Communications Controller                                     NCC     Network Control Center                                                NCC-RE  Network Communications Controller Radio frequency                             Equipment                                                             NCC-TE  Network Communications Controller Terminal                                    Equipment                                                             NCS     Network Control System                                                NE      Network Engineering                                                   NEBS    New Equipment Building System                                         NE/SE   Network Engineering/System Engineering                                NIM     Network Module                                                        NM      Network Module                                                        NMP     Network Management Process                                            NMS     Network Management System                                             NMS/CMIS                                                                              Network Management System/Customer Management                                 Information System                                                    NOC     Network Operations Center                                             NOC-FES Network Operations Center-Feederlink Earth Station                    NPA     Numbering Plan Area                                                   NRZ     Non-Return to Zero                                                    NT      Northern Telecom                                                      NTL     Northern Telecom Limited                                              NTP     Northern Telecom Practice                                             NVM     Non-Volatile Memory                                                   OA&M    Operation, Administration, and Maintenance                            O&M     Operations and Maintenance                                            OJJ     On the Job Training                                                   OM      Operational Measurements (from GWS)                                   OS      Operating System                                                      OSF     Open Software Foundation                                              OSI     Open Systems Interconnection                                          OSR     Operational Support Review                                            PA      Product Assurance                                                     PAC     Pre-emption Acknowledge Message                                       PAD     Packet Assembler/Disassembler                                         PAP     Product Assurance Plan                                                PBX     Private Branch Exchange                                               PC      Process Control                                                       PCM     Pulse Code Modulation                                                 PC-RFMCP                                                                              PC Based RFM Control Processor                                        PC-SCP  PC Based Systems Control Processor                                    PCSTR   Physical Channel Statistics Request                                   PCT     Provisioning Criteria Table                                           PCU     Pilot Control Unit                                                    PCU     Pilot Channel Unit                                                    PDAMA   Priority Demand Assignment Multiple Access                            PDN     Packet Data Network                                                   PDR     Preliminary Design Review                                             PDU     Protocol Data Unit                                                    PE      Protocol Extension                                                    PER     Packet Error Rate                                                     PERSP   Packet Error Rate Sample Period                                       PERT    Packet Error Rate Threshold                                           PIP     Program Implementation Plan                                           PLP     Packet Layer Protocol                                                 PLT     Pilot                                                                 PMR     Project Management Review                                             PMT     Pre-emption Message                                                   PN      Private Network                                                       PN      Pseudo Noise                                                          PNIC    Private Network Identification Code                                   PPM     Pulses per Minute                                                     PS      Processor Subsystem                                                   PSDN    Private Switched Data Network                                         PSDN    Public Switched Data Network                                          PSTN    Public Switched Telephone Network                                     PTT     Push-To-Talk                                                          PVC     Performance Virtual Circuit                                           PVT     Permanent Verification Test/Performance                                       Verification Test                                                     Q       Quadrature Phased Channel                                             QA      Quality Assurance                                                     Q bit   `Qualified Data` bit in X.25                                          QPSK    Quadrature Phase Shift Keying                                         RAM     Random Access Memory                                                  RAM     Reliability, Availability, Maintainability                            RDB     Relational DataBase                                                   REMS    Remote Environmental Monitoring System                                Req     Requirement                                                           Rev     Revision                                                              RF      Radio Frequency                                                       RFE     Radio Frequency Equipment                                             RF IFL  Radio Frequency Inter Facility Link                                   RFM     Radio Frequency Monitor                                               RFP     Request For Proposal                                                  RFS     Radio Frequency Subsystem                                             RHCP    Right Hand Circularly Polarized                                       RMS     Remote Monitoring Station                                             RMS     Remote Monitor Subsystem                                              RNO     Remote NOC Operator                                                   ROM     Read Only Memory                                                      RR      Receiver Ready                                                        RS      Requirements Specification                                            RS-232C Electronics Industry Standard for unbalanced data                             circuits                                                              RSP     Radio Standard Procedure                                              RTIN    Reverse Terminal Identification Number                                RTM     Requirements Traceability Matrix                                      RTP     Reliable Transaction Protocol                                         RTR     Reliable Transaction Router                                           RTS     Reliable Transaction Service                                          RTS     Receiver/Tuner System                                                 Rx      receive                                                               S/W     Software                                                              SCADA   Supervisory Control and Data Acquisition                              SCCP    Signaline Connection Control Part                                     SCPC    Single Channel Per Carrier                                            SCR     Software Change Request                                               SCS     System Common Software                                                SCU     Signaling Channel Unit                                                SDD     Software Design Description                                           SDID    Seller Data Item Description                                          SDLC    Synchronous Data Link Control                                         SDP     Software Development Plan                                             SDPAP   Software Development Product Assurance Plan                           SDR     System Design Review                                                  SDRL    Seller Data Requirements List                                         SE      Systems Engineering                                                   SEC     Setup Complete Message                                                SEDP    Software Engineering Development Plan                                 SEE     Software Engineering Environment                                      SEEP    Software Engineering Environment Plan                                 SID     System Identifier Code                                                SIF     System Integration Facility                                           SIT     Special Information Tones                                             SLOC    Source Lines of Code                                                  SLSS    Station Logic and Signaling Subsystem                                 SM      Site Manager                                                          SMAC    Station Monitor Alarm and Control Subsystem                           SMDS    Satellite Mobile Data Service                                         SMP     Software Management Plan                                              SMRS    Satellite Mobile Radio Service                                        SMSC    Satellite Mobile Switching Center                                     SMTS    Satellite Mobile Telephone Service                                    SNA     Systems Network Architecture                                          SNAC    Satellite Network Access Controller                                   SNACS   Satellite Network Access Controller Subsystem                         SNMP    Simple Network Management Protocol                                    SNR     Signal to Noise Ratio                                                 SOC     Satellite Operation Center                                            SOW     Statement of Work                                                     SP      Start Pulse                                                           SPAP    Software Product Assurance Plan                                       SPP     Satellite Protocol Processor                                          SQL     Software Query Language                                               SRR     Systems Requirements Review                                           SRS     Software Requirements Specification                                   SS7     Signaling System No. 7                                                SSA     Sloppy Slotted Aloha                                                  SSTS    Satellite Transmission Systems, Inc.                                  STP     Signal Transfer Point                                                 STP     System Test Program                                                   STS     System Test Station.                                                  STSI    Satellite Transmission Systems, Inc.                                  SU      Signaling Unit                                                        SUES    Shared-Use Earth Station                                              SVC     Switched Virtual Circuit                                              SVVP    Software Verification and Validation Plan                             SVVPR   Software Verification and Validation Plan Review                      S/W     Software                                                              [TI]    Top Level Specification                                               T- 1    Digital Transmission link, 1.544 Mega-bits per                                second                                                                TCP/IP  Transmission Control Protocol/Internet Protocol                       TCAP    Transactions Capabilities Application Part                            TCF     Training Check Frame                                                  TD      Transmission Demonstration                                            TDM     Time Division Multiplex                                               TDMA    Time Division Multiple Access                                         TDMSI   Time Division Multiplex Selector ID                                   TE      Terminal Equipment                                                    Telecom Telephonic Communications                                             TDM     Time Division Multiplex                                               TDMA    TDM Access                                                            TID     Terminal Identification                                               TIM     Timing                                                                TIM     Technical Interchange Meeting                                         TIN     Terminal Identification Number                                        TIS     Terrestrial Interface Subsystem                                       TLCSC   Top Level Computer Software Component                                 TLS     Top Level Specification                                               TMI     Telesat Mobile Incorporated                                           TMS     Test and Monitor Station                                              TNI     Terrestrial Network Interface                                         TPP     Test Plan and Procedure                                               TT&C    Telemetry, Tracking and Control                                       Tx      Transmit                                                              UCN     Up CoNverter                                                          UDS     Unacknowledged Data Delivery Service                                  UIS     User Interface Subsystem                                              UPC     Uplink Power Control                                                  UTR     Universal Tone Receiver                                               UW      Unique Words                                                          V&V     Verification and Validation                                           VAC     Value-Added Carrier                                                   VAX     Model Identification of a Digital Equipment                                   Corporation system                                                    VAX     Virtual Address extension (proprietary name used                              by DEC for some of its computer systems)                              VCN     Virtual Circuit Number                                                VF      Voice Frequency                                                       VLR     Visitor Location Register                                             VN      Virtual Network                                                       VPN     Virtual Private Network                                               VUP     VAX Unit of Processing                                                V.22bis Modem Standard for 24( )0 Baud Service Over                                   Telephone Lines                                                       V.25    Procedure for setting up a data connection on the                             Public Switched Telephone Network                                     V.26, V.28                                                                            Electrical specification of interchange                                       circuits at both the Data Terminal Equipment                                  and Data Communications Equipment sides of the                                interface (similar to RS-232-C)                                       V.32    High Speed Serial Link, Physical Layer Definition                     V.35    X.25 physical layer interface used to access                                  wideband channels (at data rates up to 64 kbit/s)                     WAN     Wide Area Network                                                     XCR     X.25 Configuration Request                                            XICD    External Interface Control Document                                   XICWG   External Interface Control Working Group                              X.3     Specification for facilities provided by the                                  Packet Assembler/Disassembler                                         X.21    X.25 physical layer interface for Data Terminal                               Equipment and Data Communications Equipment using                             synchronous transmission facilities                                   X.21bis X.25 physical layer interface for Data Terminal                               Equipment designed for interfacing to synchronous                             V-series modems to access data networks                               X.25    Specification for interface between Data Terminal                             Equipment and Data Communications Equipment for                               terminals operating in packet mode                                    X.28    Specification for interaction between loval                                   terminal and Packet Assembler/Disassembler                            X.29    Specification for interaction between Packet                                  Assembler/Disassembler and remote packet mode                                 terminal                                                              ______________________________________                                    

What is claimed is:
 1. In a mobile satellite system including asatellite communication switching office having a satellite antenna forreceiving/transmitting a satellite message via a satellite from/to avehicle using a mobile communication system, a central controllerreceiving/transmitting the satellite message from/to the satellitecommunication switching office issued from the vehicle via thesatellite, a method of providing satellite communication and satellitemanagement for multiple users in a virtual network arrangement, saidmethod comprising the steps of:(a) first and second mobile earthterminals (METs) registering with the mobile satellite system; (b) thefirst MET selecting a virtual network identifier (VN ID) representing avirtual network group including at least the first and second METs toestablish voice communication therewith; (c) the first MET transmittingthe VN ID to the central controller; (d) the central controllerreceiving the VN ID, allocating a frequency for the virtual networkgroup, and broadcasting the message to the virtual network groupincluding the second MET informing the virtual network group of theallocated frequency and the voice communication associated therewith;(e) the second MET tuning to the frequency in response to the messagebroadcast by the central controller; and (f) the first and second METscommunicating with each other on the frequency.
 2. The method accordingto claim 1, further comprising the steps of:(1) a third MET included inthe virtual network group registering with the mobile satellite system;(2) the central controller broadcasting the message to the virtualnetwork group including the third MET informing the virtual networkgroup of the allocated frequency and the voice communication associatedtherewith; and (3) the third MET tuning to the allocated frequency forthe virtual network group to gain access thereto and communicate withthe first and second METs.
 3. The method according to claim 1, whereinthe central controller controls the satellite communication of thevirtual network arrangement including virtual network parameters used bythe first and second METs.
 4. The method according to claim 1, whereinthe central controller collects billing information regarding thesatellite communication and transmits the billing information to themobile satellite system, and wherein the mobile satellite system chargesa service fee to a customer that has requested the virtual networkarrangement.
 5. The method according to claim 1, further comprising thesteps of:(1) a non-MET accessing the mobile satellite system via one ofa public switched telephone network and a cellular network to initiate acommunication with the virtual network group including at least one ofthe first and second METs; (2) the central controller broadcasting themessage to the virtual network group informing the virtual network groupof the allocated frequency and the voice communication associatedtherewith; and (3) the at least one of the first and second METs tuningto the frequency in response to the message broadcast by the centralcontroller to communicate with the non-MET in the virtual networkarrangement.
 6. The method according to claim 1, further comprising thesteps of:(1) the first MET selecting the virtual network identifier (VNID) representing the virtual network group including the first MET and anon-MET serviced by one of a public switched telephone network and acellular network to establish voice communication therewith; (2) thefirst MET transmitting the VN ID to the central controller; (3) thecentral controller receiving the VN ID, determining that the virtualnetwork group includes the non-MET, and broadcasting a non-MET messageto the one of the public switched telephone network and the cellularnetwork including the voice communication associated therewith; and (4)the one of the public switched telephone network and the cellularnetwork receiving the non-MET message from the central controller andtransmitting the non-MET message to the non-MET to establish the virtualnetwork arrangement between the MET and the non-MET.
 7. In a mobilesatellite system including a satellite communication switching officehaving a satellite antenna for receiving/transmitting a satellitemessage via a satellite from/to a vehicle using a mobile communicationsystem, a central controller receiving/transmitting the satellitemessage from/to the satellite communication switching office issued fromthe vehicle via the satellite, a system for providing satellitecommunication between multiple users in a virtual network arrangement,comprising:first and second mobile earth terminals (METs) responsivelyconnected to and registering with the mobile satellite system, the firstMET selecting a virtual network identifier (VN ID) representing avirtual network group including the first and second METs to establishvoice communication therewith and transmitting the VN ID; and a centralcontroller responsively connected to the first and second METs, thecentral controller receiving the VN ID from the first MET, validatingthe first MET for communication, validating the VN ID, allocating afrequency for the virtual network group, and broadcasting the message tothe virtual network group including the second MET informing the virtualnetwork group of the allocated frequency and the voice communicationassociated therewith, the second MET tuning to the frequency in responseto the message broadcast by the central controller, and the centralcontroller assigning the first MET as current speaker for the virtualnetwork group.
 8. The system according to claim 7, wherein the centralcontroller controls the satellite communication including virtualnetwork parameters used by the first and second METs.
 9. The systemaccording to claim 7, wherein the central controller collects billinginformation regarding the satellite communication and transmits thebilling information to the mobile satellite system, and wherein themobile satellite system charges a service fee to a customer that hasrequested the virtual network arrangement.
 10. The system according toclaim 7, whereina non-MET accesses the mobile satellite system via oneof a public switched telephone network and a cellular network toinitiate a communication with the virtual network group including atleast one of the first and second METs, the central controllerbroadcasts the message to the virtual network group informing thevirtual network group of the allocated frequency and the voicecommunication associated therewith, and the at least one of the firstand second METs tunes to the frequency in response to the messagebroadcast by the central controller to communicate with the non-MET inthe virtual network arrangement.
 11. The system according to claim 7,whereinthe first MET selects the virtual network identifier (VN ID)representing the virtual network group including the first MET and anon-MET serviced by one of a public switched telephone network and acellular network to establish voice communication therewith, andtransmits the VN ID to the central controller, the central controllerreceives the VN ID, determines that the virtual network group includesthe non-MET, and broadcasts a non-MET message to the one of the publicswitched telephone network and the cellular network including the voicecommunication associated therewith, and the one of the public switchedtelephone network and the cellular network receives the non-MET messagefrom the central controller and transmits the non-MET message to thenon-MET to establish the virtual network arrangement between the MET andthe non-MET.
 12. The system according to claim 7, further comprising athird MET responsively connected to said central controller and includedin the virtual network group registering with the mobile satellitesystem, and whereinthe central controller broadcasts the message to thevirtual network group including the third MET informing the virtualnetwork group of the allocated frequency and the voice communicationassociated therewith, the third MET generating a scrambling vector foraccess to the voice communication, and tuning to the allocated frequencyfor the virtual network group using the scrambling vector to gain accessthereto.